4.4.18-stable review

This is the start of the stable review cycle for the 4.4.18 release. There are 49 patches in this series, all will be posted as a response to this one. If anyone has any issues with these being applied, please let me know.

Responses should be made by Tue Aug 16 20:22:43 UTC 2016. Anything received after that time might be too late.

The whole patch series can be found in one patch at:

	kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.4.18-rc1.gz

or in the git tree and branch at:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.4.y
and the diffstat can be found below.

thanks,

greg k-h

-------------
Pseudo-Shortlog of commits:

Greg Kroah-Hartman <[email protected]>

    Linux 4.4.18-rc1

Vegard Nossum <[email protected]>
ext4: fix reference counting bug on block allocation error

Vegard Nossum <[email protected]>
ext4: short-cut orphan cleanup on error

Theodore Ts'o <[email protected]>
ext4: validate s_reserved_gdt_blocks on mount

Vegard Nossum <[email protected]>
ext4: don't call ext4_should_journal_data() on the journal inode

Jan Kara <[email protected]>
ext4: fix deadlock during page writeback

Vegard Nossum <[email protected]>
ext4: check for extents that wrap around

Herbert Xu <[email protected]>
crypto: scatterwalk - Fix test in scatterwalk_done

Herbert Xu <[email protected]>
crypto: gcm - Filter out async ghash if necessary

Wei Fang <[email protected]>
fs/dcache.c: avoid soft-lockup in dput()

Wei Fang <[email protected]>

    fuse: fix wrong assignment of ->flags in fuse_send_init()

Maxim Patlasov <[email protected]>

    fuse: fuse_flush must check mapping->flags for errors

Alexey Kuznetsov <[email protected]>
fuse: fsync() did not return IO errors

Fabian Frederick <[email protected]>
sysv, ipc: fix security-layer leaking

Vegard Nossum <[email protected]>
block: fix use-after-free in seq file

David Howells <[email protected]>
x86/syscalls/64: Add compat_sys_keyctl for 32-bit userspace

Vladimir Davydov <[email protected]>
mm: memcontrol: fix memcg id ref counter on swap charge move

Vladimir Davydov <[email protected]>
mm: memcontrol: fix swap counter leak on swapout from offline cgroup

Johannes Weiner <[email protected]>
mm: memcontrol: fix cgroup creation failure after many small jobs

Matt Roper <[email protected]>
drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2)

Toshi Kani <[email protected]>

    x86/mm/pat: Fix BUG_ON() in mmap_mem() on QEMU/i386

Toshi Kani <[email protected]>
x86/pat: Document the PAT initialization sequence

Toshi Kani <[email protected]>
x86/xen, pat: Remove PAT table init code from Xen

Toshi Kani <[email protected]>
x86/mtrr: Fix PAT init handling when MTRR is disabled

Toshi Kani <[email protected]>
x86/mtrr: Fix Xorg crashes in Qemu sessions

Toshi Kani <[email protected]>
x86/mm/pat: Replace cpu_has_pat with boot_cpu_has()

Toshi Kani <[email protected]>
x86/mm/pat: Add pat_disable() interface

Toshi Kani <[email protected]>
x86/mm/pat: Add support of non-default PAT MSR setting

Linus Torvalds <[email protected]>
devpts: clean up interface to pty drivers

Theodore Ts'o <[email protected]>
random: strengthen input validation for RNDADDTOENTCNT

John Johansen <[email protected]>
apparmor: fix ref count leak when profile sha1 hash is read

Michael Holzheu <[email protected]>
Revert "s390/kdump: Clear subchannel ID to signal non-CCW/SCSI IPL"

David Howells <[email protected]>
KEYS: 64-bit MIPS needs to use compat_sys_keyctl for 32-bit userspace

Dave Weinstein <[email protected]>
arm: oabi compat: add missing access checks

Bjørn Mork <[email protected]>
cdc_ncm: do not call usbnet_link_change from cdc_ncm_bind

Mika Westerberg <[email protected]>
i2c: i801: Allow ACPI SystemIO OpRegion to conflict with PCI BAR

Hector Marco-Gisbert <[email protected]>

    x86/mm/32: Enable full randomization on i386 and X86_32

Benjamin Tissoires <[email protected]>
HID: sony: do not bail out when the sixaxis refuses the output report

Christophe Le Roy <[email protected]>
PNP: Add Broadwell to Intel MCH size workaround

Josh Boyer <[email protected]>
PNP: Add Haswell-ULT to Intel MCH size workaround

Hannes Reinecke <[email protected]>
scsi: ignore errors from scsi_dh_add_device()

Ben Hutchings <[email protected]>
ipath: Restrict use of the write() interface

Soheil Hassas Yeganeh <[email protected]>
tcp: consider recv buf for the initial window scale

Manish Chopra <[email protected]>
qed: Fix setting/clearing bit in completion bitmap

Vegard Nossum <[email protected]>
net/irda: fix NULL pointer dereference on memory allocation failure

Florian Fainelli <[email protected]>
net: bgmac: Fix infinite loop in bgmac_dma_tx_add()

Beniamino Galvani <[email protected]>
bonding: set carrier off for devices created through netlink

Julian Anastasov <[email protected]>
ipv4: reject RTNH_F_DEAD and RTNH_F_LINKDOWN from user space

Jason Baron <[email protected]>
tcp: enable per-socket rate limiting of all 'challenge acks'

Eric Dumazet <[email protected]>
tcp: make challenge acks less predictable

-------------

Diffstat:

 Documentation/x86/pat.txt                   |  32 ++++++
 Makefile                                    |   4 +-
 arch/arm/kernel/sys_oabi-compat.c           |   8 +-
 arch/mips/kernel/scall64-n32.S              |   2 +-
 arch/mips/kernel/scall64-o32.S              |   2 +-
 arch/s390/kernel/ipl.c                      |   7 --
 arch/x86/entry/syscalls/syscall_32.tbl      |   2 +-
 arch/x86/include/asm/mtrr.h                 |   6 +-
 arch/x86/include/asm/pat.h                  |   2 +-
 arch/x86/kernel/cpu/mtrr/generic.c          |  24 +++--
 arch/x86/kernel/cpu/mtrr/main.c             |  13 ++-
 arch/x86/kernel/cpu/mtrr/mtrr.h             |   1 +
 arch/x86/mm/mmap.c                          |  14 +--
 arch/x86/mm/pat.c                           | 109 +++++++++++++--------
 arch/x86/xen/enlighten.c                    |   9 --
 block/genhd.c                               |   1 +
 crypto/gcm.c                                |   4 +-
 crypto/scatterwalk.c                        |   3 +-
 drivers/char/random.c                       |  13 +--
 drivers/gpu/drm/i915/intel_pm.c             |  14 ++-
 drivers/hid/hid-sony.c                      |   6 +-
 drivers/i2c/busses/i2c-i801.c               | 103 ++++++++++++++++++--
 drivers/net/bonding/bond_netlink.c          |   6 +-
 drivers/net/ethernet/broadcom/bgmac.c       |   2 +-
 drivers/net/ethernet/qlogic/qed/qed_spq.c   |   7 +-
 drivers/net/usb/cdc_ncm.c                   |  20 +---
 drivers/pnp/quirks.c                        |   2 +
 drivers/scsi/scsi_sysfs.c                   |   7 +-
 drivers/staging/rdma/ipath/ipath_file_ops.c |   5 +
 drivers/tty/pty.c                           |  63 ++++++------
 fs/dcache.c                                 |   7 +-
 fs/devpts/inode.c                           |  49 +++++-----
 fs/ext4/balloc.c                            |   3 +
 fs/ext4/extents.c                           |   8 +-
 fs/ext4/inode.c                             |  35 +++++--
 fs/ext4/mballoc.c                           |  17 +---
 fs/ext4/super.c                             |  17 ++++
 fs/fuse/file.c                              |  24 +++++
 fs/fuse/inode.c                             |   2 +-
 include/linux/devpts_fs.h                   |  34 ++-----
 include/linux/memcontrol.h                  |   8 ++
 ipc/msg.c                                   |   2 +-
 ipc/sem.c                                   |  12 +--
 mm/memcontrol.c                             | 146 +++++++++++++++++++++++-----
 mm/slab_common.c                            |   2 +-
 net/ipv4/fib_semantics.c                    |   6 ++
 net/ipv4/tcp_input.c                        |  54 +++++-----
 net/ipv4/tcp_output.c                       |   3 +-
 net/irda/af_irda.c                          |   7 +-
 security/apparmor/apparmorfs.c              |   1 +
 50 files changed, 626 insertions(+), 302 deletions(-)

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <[email protected]>

[ Upstream commit 75ff39ccc1bd5d3c455b6822ab09e533c551f758 ]

Yue Cao claims that current host rate limiting of challenge ACKS (RFC 5961) could leak enough information to allow a patient attacker to hijack TCP sessions. He will soon provide details in an academic paper.

This patch increases the default limit from 100 to 1000, and adds some randomization so that the attacker can no longer hijack sessions without spending a considerable amount of probes.

Based on initial analysis and patch from Linus.

Note that we also have per socket rate limiting, so it is tempting to remove the host limit in the future.

v2: randomize the count of challenge acks per second, not the period.

---
 net/ipv4/tcp_input.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

@@ -89,7 +89,7 @@ int sysctl_tcp_adv_win_scale __read_most
 EXPORT_SYMBOL(sysctl_tcp_adv_win_scale);
 
 /* rfc5961 challenge ack rate limiting */
-int sysctl_tcp_challenge_ack_limit = 100;
+int sysctl_tcp_challenge_ack_limit = 1000;
 
 int sysctl_tcp_stdurg __read_mostly;
 int sysctl_tcp_rfc1337 __read_mostly;

@@ -3427,7 +3427,7 @@ static void tcp_send_challenge_ack(struc
 	static u32 challenge_timestamp;
 	static unsigned int challenge_count;
 	struct tcp_sock *tp = tcp_sk(sk);
-	u32 now;
+	u32 count, now;
 
 	/* First check our per-socket dupack rate limit. */
 	if (tcp_oow_rate_limited(sock_net(sk), skb,

@@ -3435,13 +3435,18 @@ static void tcp_send_challenge_ack(struc
 				 &tp->last_oow_ack_time))
 		return;
 
-	/* Then check the check host-wide RFC 5961 rate limit. */
+	/* Then check host-wide RFC 5961 rate limit. */
 	now = jiffies / HZ;
 	if (now != challenge_timestamp) {
+		u32 half = (sysctl_tcp_challenge_ack_limit + 1) >> 1;
+
 		challenge_timestamp = now;
-		challenge_count = 0;
+		WRITE_ONCE(challenge_count, half +
+			   prandom_u32_max(sysctl_tcp_challenge_ack_limit));
 	}
-	if (++challenge_count <= sysctl_tcp_challenge_ack_limit) {
+	count = READ_ONCE(challenge_count);
+	if (count > 0) {
+		WRITE_ONCE(challenge_count, count - 1);
 		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPCHALLENGEACK);
 		tcp_send_ack(sk);
 	}

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jason Baron <[email protected]>

[ Upstream commit 083ae308280d13d187512b9babe3454342a7987e ]

The per-socket rate limit for 'challenge acks' was introduced in the context of limiting ack loops:

commit f2b2c582e824 ("tcp: mitigate ACK loops for connections as tcp_sock")

And I think it can be extended to rate limit all 'challenge acks' on a per-socket basis.

Since we have the global tcp_challenge_ack_limit, this patch allows for tcp_challenge_ack_limit to be set to a large value and effectively rely on the per-socket limit, or set tcp_challenge_ack_limit to a lower value and still prevents a single connections from consuming the entire challenge ack quota.

It further moves in the direction of eliminating the global limit at some point, as Eric Dumazet has suggested. This a follow-up to:
Subject: [PATCH 4.4 02/49] tcp: make challenge acks less predictable

---
 net/ipv4/tcp_input.c |   39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

@@ -3390,6 +3390,23 @@ static int tcp_ack_update_window(struct
 	return flag;
 }
 
+static bool __tcp_oow_rate_limited(struct net *net, int mib_idx,
+				   u32 *last_oow_ack_time)
+{
+	if (*last_oow_ack_time) {
+		s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
+
+		if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
+			NET_INC_STATS_BH(net, mib_idx);
+			return true;	/* rate-limited: don't send yet! */
+		}
+	}
+
+	*last_oow_ack_time = tcp_time_stamp;
+
+	return false;	/* not rate-limited: go ahead, send dupack now! */
+}
+
 /* Return true if we're currently rate-limiting out-of-window ACKs and
  * thus shouldn't send a dupack right now. We rate-limit dupacks in
  * response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS

@@ -3403,21 +3420,9 @@ bool tcp_oow_rate_limited(struct net *ne
 	/* Data packets without SYNs are not likely part of an ACK loop. */
 	if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
 	    !tcp_hdr(skb)->syn)
-		goto not_rate_limited;
-
-	if (*last_oow_ack_time) {
-		s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
+		return false;
 
-		if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
-			NET_INC_STATS_BH(net, mib_idx);
-			return true;	/* rate-limited: don't send yet! */
-		}
-	}
-
-	*last_oow_ack_time = tcp_time_stamp;
-
-not_rate_limited:
-	return false;	/* not rate-limited: go ahead, send dupack now! */
+	return __tcp_oow_rate_limited(net, mib_idx, last_oow_ack_time);
 }
 
 /* RFC 5961 7 [ACK Throttling] */

@@ -3430,9 +3435,9 @@ static void tcp_send_challenge_ack(struc
 	u32 count, now;
 
 	/* First check our per-socket dupack rate limit. */
-	if (tcp_oow_rate_limited(sock_net(sk), skb,
-				 LINUX_MIB_TCPACKSKIPPEDCHALLENGE,
-				 &tp->last_oow_ack_time))
+	if (__tcp_oow_rate_limited(sock_net(sk),
+				   LINUX_MIB_TCPACKSKIPPEDCHALLENGE,
+				   &tp->last_oow_ack_time))
 		return;
 
 	/* Then check host-wide RFC 5961 rate limit. */

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Julian Anastasov <[email protected]>

[ Upstream commit 80610229ef7b26615dbb6cb6e873709a60bacc9f ]

Vegard Nossum is reporting for a crash in fib_dump_info when nh_dev = NULL and fib_nhs == 1:

Pid: 50, comm: netlink.exe Not tainted 4.7.0-rc5+

RIP: 0033:[<00000000602b3d18>]
RSP: 0000000062623890  EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000006261b800 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000024 RDI: 000000006245ba00
RBP: 00000000626238f0 R08: 000000000000029c R09: 0000000000000000
R10: 0000000062468038 R11: 000000006245ba00 R12: 000000006245ba00
R13: 00000000625f96c0 R14: 00000000601e16f0 R15: 0000000000000000
Kernel panic - not syncing: Kernel mode fault at addr 0x2e0, ip 0x602b3d18
CPU: 0 PID: 50 Comm: netlink.exe Not tainted 4.7.0-rc5+ #581
Stack:
 626238f0 960226a02 00000400 000000fe
 62623910 600afca7 62623970 62623a48
 62468038 00000018 00000000 00000000
Call Trace:
 [<602b3e93>] rtmsg_fib+0xd3/0x190
 [<602b6680>] fib_table_insert+0x260/0x500
 [<602b0e5d>] inet_rtm_newroute+0x4d/0x60
 [<60250def>] rtnetlink_rcv_msg+0x8f/0x270
 [<60267079>] netlink_rcv_skb+0xc9/0xe0
 [<60250d4b>] rtnetlink_rcv+0x3b/0x50
 [<60265400>] netlink_unicast+0x1a0/0x2c0
 [<60265e47>] netlink_sendmsg+0x3f7/0x470
 [<6021dc9a>] sock_sendmsg+0x3a/0x90
 [<6021e0d0>] ___sys_sendmsg+0x300/0x360
 [<6021fa64>] __sys_sendmsg+0x54/0xa0
 [<6021fac0>] SyS_sendmsg+0x10/0x20
 [<6001ea68>] handle_syscall+0x88/0x90
 [<600295fd>] userspace+0x3fd/0x500
 [<6001ac55>] fork_handler+0x85/0x90

$ addr2line -e vmlinux -i 0x602b3d18
include/linux/inetdevice.h:222
net/ipv4/fib_semantics.c:1264

Problem happens when RTNH_F_LINKDOWN is provided from user space when creating routes that do not use the flag, catched with netlink fuzzer.

Currently, the kernel allows user space to set both flags to nh_flags and fib_flags but this is not intentional, the assumption was that they are not set. Fix this by rejecting both flags with EINVAL.

---
 net/ipv4/fib_semantics.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -479,6 +479,9 @@ static int fib_get_nhs(struct fib_info *
 		if (!rtnh_ok(rtnh, remaining))
 			return -EINVAL;
 
+		if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
+			return -EINVAL;
+
 		nexthop_nh->nh_flags =
 			(cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 		nexthop_nh->nh_oif = rtnh->rtnh_ifindex;

@@ -1003,6 +1006,9 @@ struct fib_info *fib_create_info(struct
 	if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
 		goto err_inval;
 
+	if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
+		goto err_inval;
+
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 	if (cfg->fc_mp) {
 		nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Beniamino Galvani <[email protected]>

[ Upstream commit 005db31d5f5f7c31cfdc43505d77eb3ca5cf8ec6 ]

Commit e826eafa65c6 ("bonding: Call netif_carrier_off after register_netdevice") moved netif_carrier_off() from bond_init() to bond_create(), but the latter is called only for initial default devices and ones created through sysfs:

 $ modprobe bonding
 $ echo +bond1 > /sys/class/net/bonding_masters
 $ ip link add bond2 type bond
 $ grep "MII Status" /proc/net/bonding/*
 /proc/net/bonding/bond0:MII Status: down
 /proc/net/bonding/bond1:MII Status: down
 /proc/net/bonding/bond2:MII Status: up

Ensure that carrier is initially off also for devices created through netlink.

---
 drivers/net/bonding/bond_netlink.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

@@ -446,7 +446,11 @@ static int bond_newlink(struct net *src_
 	if (err < 0)
 		return err;
 
-	return register_netdevice(bond_dev);
+	err = register_netdevice(bond_dev);
+
+	netif_carrier_off(bond_dev);
+
+	return err;
 }
 
 static size_t bond_get_size(const struct net_device *bond_dev)

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Florian Fainelli <[email protected]>

[ Upstream commit e86663c475d384ab5f46cb5637e9b7ad08c5c505 ]

Nothing is decrementing the index "i" while we are cleaning up the fragments we could not successful transmit.

---
 drivers/net/ethernet/broadcom/bgmac.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -219,7 +219,7 @@ err_dma:
 	dma_unmap_single(dma_dev, slot->dma_addr, skb_headlen(skb),
 			 DMA_TO_DEVICE);
 
-	while (i > 0) {
+	while (i-- > 0) {
 		int index = (ring->end + i) % BGMAC_TX_RING_SLOTS;
 		struct bgmac_slot_info *slot = &ring->slots[index];
 		u32 ctl1 = le32_to_cpu(ring->cpu_base[index].ctl1);

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vegard Nossum <[email protected]>

[ Upstream commit d3e6952cfb7ba5f4bfa29d4803ba91f96ce1204d ]

I ran into this:

    kasan: CONFIG_KASAN_INLINE enabled
    kasan: GPF could be caused by NULL-ptr deref or user memory access
    general protection fault: 0000 [#1] PREEMPT SMP KASAN
    CPU: 2 PID: 2012 Comm: trinity-c3 Not tainted 4.7.0-rc7+ #19
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
    task: ffff8800b745f2c0 ti: ffff880111740000 task.ti: ffff880111740000
    RIP: 0010:[<ffffffff82bbf066>]  [<ffffffff82bbf066>] irttp_connect_request+0x36/0x710
    RSP: 0018:ffff880111747bb8  EFLAGS: 00010286
    RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000069dd8358
    RDX: 0000000000000009 RSI: 0000000000000027 RDI: 0000000000000048
    RBP: ffff880111747c00 R08: 0000000000000000 R09: 0000000000000000
    R10: 0000000069dd8358 R11: 1ffffffff0759723 R12: 0000000000000000
    R13: ffff88011a7e4780 R14: 0000000000000027 R15: 0000000000000000
    FS:  00007fc738404700(0000) GS:ffff88011af00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007fc737fdfb10 CR3: 0000000118087000 CR4: 00000000000006e0
    Stack:
     0000000000000200 ffff880111747bd8 ffffffff810ee611 ffff880119f1f220
     ffff880119f1f4f8 ffff880119f1f4f0 ffff88011a7e4780 ffff880119f1f232
     ffff880119f1f220 ffff880111747d58 ffffffff82bca542 0000000000000000
    Call Trace:
     [<ffffffff82bca542>] irda_connect+0x562/0x1190
     [<ffffffff825ae582>] SYSC_connect+0x202/0x2a0
     [<ffffffff825b4489>] SyS_connect+0x9/0x10
     [<ffffffff8100334c>] do_syscall_64+0x19c/0x410
     [<ffffffff83295ca5>] entry_SYSCALL64_slow_path+0x25/0x25
    Code: 41 89 ca 48 89 e5 41 57 41 56 41 55 41 54 41 89 d7 53 48 89 fb 48 83 c7 48 48 89 fa 41 89 f6 48 c1 ea 03 48 83 ec 20 4c 8b 65 10 <0f> b6 04 02 84 c0 74 08 84 c0 0f 8e 4c 04 00 00 80 7b 48 00 74
    RIP  [<ffffffff82bbf066>] irttp_connect_request+0x36/0x710
     RSP <ffff880111747bb8>
    ---[ end trace 4cda2588bc055b30 ]---

The problem is that irda_open_tsap() can fail and leave self->tsap = NULL, and then irttp_connect_request() almost immediately dereferences it.

---
 net/irda/af_irda.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

@@ -1024,8 +1024,11 @@ static int irda_connect(struct socket *s
 	}
 
 	/* Check if we have opened a local TSAP */
-	if (!self->tsap)
-		irda_open_tsap(self, LSAP_ANY, addr->sir_name);
+	if (!self->tsap) {
+		err = irda_open_tsap(self, LSAP_ANY, addr->sir_name);
+		if (err)
+			goto out;
+	}
 
 	/* Move to connecting socket, start sending Connect Requests */
 	sock->state = SS_CONNECTING;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Manish Chopra <[email protected]>

[ Upstream commit 59d3f1ceb69b54569685d0c34dff16a1e0816b19 ]

Slowpath completion handling is incorrectly changing SPQ_RING_SIZE bits instead of a single one.

---
 drivers/net/ethernet/qlogic/qed/qed_spq.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

@@ -794,13 +794,12 @@ int qed_spq_completion(struct qed_hwfn *
 			 * in a bitmap and increasing the chain consumer only
 			 * for the first successive completed entries.
 			 */
-			bitmap_set(p_spq->p_comp_bitmap, pos, SPQ_RING_SIZE);
+			__set_bit(pos, p_spq->p_comp_bitmap);
 
 			while (test_bit(p_spq->comp_bitmap_idx,
 					p_spq->p_comp_bitmap)) {
-				bitmap_clear(p_spq->p_comp_bitmap,
-					     p_spq->comp_bitmap_idx,
-					     SPQ_RING_SIZE);
+				__clear_bit(p_spq->comp_bitmap_idx,
+					    p_spq->p_comp_bitmap);
 				p_spq->comp_bitmap_idx++;
 				qed_chain_return_produced(&p_spq->chain);
 			}

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Soheil Hassas Yeganeh <[email protected]>

[ Upstream commit f626300a3e776ccc9671b0dd94698fb3aa315966 ]

tcp_select_initial_window() intends to advertise a window scaling for the maximum possible window size. To do so, it considers the maximum of net.ipv4.tcp_rmem[2] and net.core.rmem_max as the only possible upper-bounds. However, users with CAP_NET_ADMIN can use SO_RCVBUFFORCE to set the socket's receive buffer size to values larger than net.ipv4.tcp_rmem[2] and net.core.rmem_max. Thus, SO_RCVBUFFORCE is effectively ignored by tcp_select_initial_window().

To fix this, consider the maximum of net.ipv4.tcp_rmem[2], net.core.rmem_max and socket's initial buffer space.

---
 net/ipv4/tcp_output.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -239,7 +239,8 @@ void tcp_select_initial_window(int __spa
 		/* Set window scaling on max possible window
 		 * See RFC1323 for an explanation of the limit to 14
 		 */
-		space = max_t(u32, sysctl_tcp_rmem[2], sysctl_rmem_max);
+		space = max_t(u32, space, sysctl_tcp_rmem[2]);
+		space = max_t(u32, space, sysctl_rmem_max);
 		space = min_t(u32, space, *window_clamp);
 		while (space > 65535 && (*rcv_wscale) < 14) {
 			space >>= 1;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <[email protected]>

Commit e6bd18f57aad ("IB/security: Restrict use of the write() interface") fixed a security problem with various write() implementations in the Infiniband subsystem. In older kernel versions the ipath_write() function has the same problem and needs the same restriction. (The ipath driver has been completely removed upstream.)

---
 drivers/staging/rdma/ipath/ipath_file_ops.c |    5 +++++
 1 file changed, 5 insertions(+)

@@ -45,6 +45,8 @@
 #include <linux/uio.h>
 #include <asm/pgtable.h>
 
+#include <rdma/ib.h>
+
 #include "ipath_kernel.h"
 #include "ipath_common.h"
 #include "ipath_user_sdma.h"

@@ -2243,6 +2245,9 @@ static ssize_t ipath_write(struct file *
 	ssize_t ret = 0;
 	void *dest;
 
+	if (WARN_ON_ONCE(!ib_safe_file_access(fp)))
+		return -EACCES;
+
 	if (count < sizeof(cmd.type)) {
 		ret = -EINVAL;
 		goto bail;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hannes Reinecke <[email protected]>

commit 221255aee67ec1c752001080aafec0c4e9390d95 upstream.

device handler initialisation might fail due to a number of reasons. But as device_handlers are optional this shouldn't cause us to disable the device entirely.
So just ignore errors from scsi_dh_add_device().

---
 drivers/scsi/scsi_sysfs.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

@@ -1058,11 +1058,12 @@ int scsi_sysfs_add_sdev(struct scsi_devi
 	}
 
 	error = scsi_dh_add_device(sdev);
-	if (error) {
+	if (error)
+		/*
+		 * device_handler is optional, so any error can be ignored
+		 */
 		sdev_printk(KERN_INFO, sdev,
 				"failed to add device handler: %d\n", error);
-		return error;
-	}
 
 	device_enable_async_suspend(&sdev->sdev_dev);
 	error = device_add(&sdev->sdev_dev);

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Josh Boyer <[email protected]>

commit ed1f0eeebaeeb7f790e9e7642116a208581e5bfc upstream.

Add device ID 0x0a04 for Haswell-ULT to the list of devices with MCH problems.

[    0.188604] pnp: PnP ACPI init
[    0.189044] system 00:00: [mem 0x00000000-0x0009ffff] could not be reserved
[    0.189048] system 00:00: [mem 0x000c0000-0x000c3fff] could not be reserved
[    0.189050] system 00:00: [mem 0x000c4000-0x000c7fff] could not be reserved
[    0.189052] system 00:00: [mem 0x000c8000-0x000cbfff] could not be reserved
[    0.189054] system 00:00: [mem 0x000cc000-0x000cffff] could not be reserved
[    0.189056] system 00:00: [mem 0x000d0000-0x000d3fff] has been reserved
[    0.189058] system 00:00: [mem 0x000d4000-0x000d7fff] has been reserved
[    0.189060] system 00:00: [mem 0x000d8000-0x000dbfff] has been reserved
[    0.189061] system 00:00: [mem 0x000dc000-0x000dffff] has been reserved
[    0.189063] system 00:00: [mem 0x000e0000-0x000e3fff] could not be reserved
[    0.189065] system 00:00: [mem 0x000e4000-0x000e7fff] could not be reserved
[    0.189067] system 00:00: [mem 0x000e8000-0x000ebfff] could not be reserved
[    0.189069] system 00:00: [mem 0x000ec000-0x000effff] could not be reserved
[    0.189071] system 00:00: [mem 0x000f0000-0x000fffff] could not be reserved
[    0.189073] system 00:00: [mem 0x00100000-0xdf9fffff] could not be reserved
[    0.189075] system 00:00: [mem 0xfec00000-0xfed3ffff] could not be reserved
[    0.189078] system 00:00: [mem 0xfed4c000-0xffffffff] could not be reserved
[    0.189082] system 00:00: Plug and Play ACPI device, IDs PNP0c01 (active)
[    0.189216] system 00:01: [io  0x1800-0x189f] could not be reserved
[    0.189220] system 00:01: [io  0x0800-0x087f] has been reserved
[    0.189222] system 00:01: [io  0x0880-0x08ff] has been reserved
[    0.189224] system 00:01: [io  0x0900-0x097f] has been reserved
[    0.189226] system 00:01: [io  0x0980-0x09ff] has been reserved
[    0.189229] system 00:01: [io  0x0a00-0x0a7f] has been reserved
[    0.189231] system 00:01: [io  0x0a80-0x0aff] has been reserved
[    0.189233] system 00:01: [io  0x0b00-0x0b7f] has been reserved
[    0.189235] system 00:01: [io  0x0b80-0x0bff] has been reserved
[    0.189238] system 00:01: [io  0x15e0-0x15ef] has been reserved
[    0.189240] system 00:01: [io  0x1600-0x167f] has been reserved
[    0.189242] system 00:01: [io  0x1640-0x165f] has been reserved
[    0.189246] system 00:01: [mem 0xf8000000-0xfbffffff] could not be reserved
[    0.189249] system 00:01: [mem 0x00000000-0x00000fff] could not be reserved
[    0.189251] system 00:01: [mem 0xfed1c000-0xfed1ffff] has been reserved
[    0.189254] system 00:01: [mem 0xfed10000-0xfed13fff] has been reserved
[    0.189256] system 00:01: [mem 0xfed18000-0xfed18fff] has been reserved
[    0.189258] system 00:01: [mem 0xfed19000-0xfed19fff] has been reserved
[    0.189261] system 00:01: [mem 0xfed45000-0xfed4bfff] has been reserved
[    0.189264] system 00:01: Plug and Play ACPI device, IDs PNP0c02 (active)
[....]
[    0.583653] resource sanity check: requesting [mem 0xfed10000-0xfed15fff], which spans more than pnp 00:01 [mem 0xfed10000-0xfed13fff]
[    0.583654] ------------[ cut here ]------------
[    0.583660] WARNING: CPU: 0 PID: 1 at arch/x86/mm/ioremap.c:198 __ioremap_caller+0x2c5/0x380()
[    0.583661] Info: mapping multiple BARs. Your kernel is fine.
[    0.583662] Modules linked in:

[    0.583666] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.3.3-303.fc23.x86_64 #1
[    0.583668] Hardware name: LENOVO 20AR001GXS/20AR001GXS, BIOS GJET86WW (2.36 ) 12/04/2015
[    0.583670]  0000000000000000 0000000014cf7e59 ffff880214a1baf8 ffffffff813a625f
[    0.583673]  ffff880214a1bb40 ffff880214a1bb30 ffffffff810a07c2 00000000fed10000
[    0.583675]  ffffc90000cb8000 0000000000006000 0000000000000000 ffff8800d6381040
[    0.583678] Call Trace:
[    0.583683]  [<ffffffff813a625f>] dump_stack+0x44/0x55
[    0.583686]  [<ffffffff810a07c2>] warn_slowpath_common+0x82/0xc0
[    0.583688]  [<ffffffff810a085c>] warn_slowpath_fmt+0x5c/0x80
[    0.583692]  [<ffffffff810a6fba>] ? iomem_map_sanity_check+0xba/0xd0
[    0.583695]  [<ffffffff81065835>] __ioremap_caller+0x2c5/0x380
[    0.583698]  [<ffffffff81065907>] ioremap_nocache+0x17/0x20
[    0.583701]  [<ffffffff8103a119>] snb_uncore_imc_init_box+0x79/0xb0
[    0.583705]  [<ffffffff81038900>] uncore_pci_probe+0xd0/0x1b0
[    0.583707]  [<ffffffff813efda5>] local_pci_probe+0x45/0xa0
[    0.583710]  [<ffffffff813f118d>] pci_device_probe+0xfd/0x140
[    0.583713]  [<ffffffff814d9b52>] driver_probe_device+0x222/0x480
[    0.583715]  [<ffffffff814d9e34>] __driver_attach+0x84/0x90
[    0.583717]  [<ffffffff814d9db0>] ? driver_probe_device+0x480/0x480
[    0.583720]  [<ffffffff814d762c>] bus_for_each_dev+0x6c/0xc0
[    0.583722]  [<ffffffff814d930e>] driver_attach+0x1e/0x20
[    0.583724]  [<ffffffff814d8e4b>] bus_add_driver+0x1eb/0x280
[    0.583727]  [<ffffffff81d6af1a>] ? uncore_cpu_setup+0x12/0x12
[    0.583729]  [<ffffffff814da680>] driver_register+0x60/0xe0
[    0.583733]  [<ffffffff813ef78c>] __pci_register_driver+0x4c/0x50
[    0.583736]  [<ffffffff81d6affc>] intel_uncore_init+0xe2/0x2e6
[    0.583738]  [<ffffffff81d6af1a>] ? uncore_cpu_setup+0x12/0x12
[    0.583741]  [<ffffffff81002123>] do_one_initcall+0xb3/0x200
[    0.583745]  [<ffffffff810be500>] ? parse_args+0x1a0/0x4a0
[    0.583749]  [<ffffffff81d5c1c8>] kernel_init_freeable+0x189/0x223
[    0.583752]  [<ffffffff81775c40>] ? rest_init+0x80/0x80
[    0.583754]  [<ffffffff81775c4e>] kernel_init+0xe/0xe0
[    0.583758]  [<ffffffff81781adf>] ret_from_fork+0x3f/0x70
[    0.583760]  [<ffffffff81775c40>] ? rest_init+0x80/0x80
[    0.583765] ---[ end trace 077c426a39e018aa ]---

00:00.0 Host bridge [0600]: Intel Corporation Haswell-ULT DRAM Controller [8086:0a04] (rev 0b)
Subsystem: Lenovo Device [17aa:220c]
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx-
Latency: 0
Capabilities: <access denied>
Kernel driver in use: hsw_uncore

---
 drivers/pnp/quirks.c |    1 +
 1 file changed, 1 insertion(+)

@@ -342,6 +342,7 @@ static void quirk_amd_mmconfig_area(stru
 /* Device IDs of parts that have 32KB MCH space */
 static const unsigned int mch_quirk_devices[] = {
 	0x0154,	/* Ivy Bridge */
+	0x0a04, /* Haswell-ULT */
 	0x0c00,	/* Haswell */
 };
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Christophe Le Roy <[email protected]>

commit a77060f07ffc6ac978e280e738302f3e5572a99e upstream.

Add device ID 0x1604 for Broadwell to commit cb171f7abb9a ("PNP:
Work around BIOS defects in Intel MCH area reporting").

  system 00:01: [io  0x1800-0x189f] could not be reserved
  system 00:01: [io  0x0800-0x087f] has been reserved
  system 00:01: [io  0x0880-0x08ff] has been reserved
  system 00:01: [io  0x0900-0x097f] has been reserved
  system 00:01: [io  0x0980-0x09ff] has been reserved
  system 00:01: [io  0x0a00-0x0a7f] has been reserved
  system 00:01: [io  0x0a80-0x0aff] has been reserved
  system 00:01: [io  0x0b00-0x0b7f] has been reserved
  system 00:01: [io  0x0b80-0x0bff] has been reserved
  system 00:01: [io  0x15e0-0x15ef] has been reserved
  system 00:01: [io  0x1600-0x167f] has been reserved
  system 00:01: [io  0x1640-0x165f] has been reserved
  system 00:01: [mem 0xf8000000-0xfbffffff] could not be reserved
  system 00:01: [mem 0xfed1c000-0xfed1ffff] has been reserved
  system 00:01: [mem 0xfed10000-0xfed13fff] has been reserved
  system 00:01: [mem 0xfed18000-0xfed18fff] has been reserved
  system 00:01: [mem 0xfed19000-0xfed19fff] has been reserved
  system 00:01: [mem 0xfed45000-0xfed4bfff] has been reserved
  system 00:01: Plug and Play ACPI device, IDs PNP0c02 (active)
  [...]
  resource sanity check: requesting [mem 0xfed10000-0xfed15fff], which spans more than pnp 00:01 [mem 0xfed10000-0xfed13fff]
  ------------[ cut here ]------------
  WARNING: CPU: 2 PID: 1 at /build/linux-CrHvZ_/linux-4.2.6/arch/x86/mm/ioremap.c:198 __ioremap_caller+0x2ee/0x360()
  Info: mapping multiple BARs. Your kernel is fine.
  Modules linked in:
  CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.2.0-1-amd64 #1 Debian 4.2.6-1
  Hardware name: LENOVO 20CKCTO1WW/20CKCTO1WW, BIOS N11ET34W (1.10 ) 08/20/2015
   0000000000000000 ffffffff817e6868 ffffffff8154e2f6 ffff8802241efbf8
   ffffffff8106e5b1 ffffc90000e98000 0000000000006000 ffffc90000e98000
   0000000000006000 0000000000000000 ffffffff8106e62a ffffffff817e68c8
  Call Trace:
   [<ffffffff8154e2f6>] ? dump_stack+0x40/0x50
   [<ffffffff8106e5b1>] ? warn_slowpath_common+0x81/0xb0
   [<ffffffff8106e62a>] ? warn_slowpath_fmt+0x4a/0x50
   [<ffffffff810742a3>] ? iomem_map_sanity_check+0xb3/0xc0
   [<ffffffff8105dade>] ? __ioremap_caller+0x2ee/0x360
   [<ffffffff81036ae6>] ? snb_uncore_imc_init_box+0x66/0x90
   [<ffffffff810351a8>] ? uncore_pci_probe+0xc8/0x1a0
   [<ffffffff81302d7f>] ? local_pci_probe+0x3f/0xa0
   [<ffffffff81303ea4>] ? pci_device_probe+0xc4/0x110
   [<ffffffff813d9b1e>] ? driver_probe_device+0x1ee/0x450
   [<ffffffff813d9dfb>] ? __driver_attach+0x7b/0x80
   [<ffffffff813d9d80>] ? driver_probe_device+0x450/0x450
   [<ffffffff813d796a>] ? bus_for_each_dev+0x5a/0x90
   [<ffffffff813d9091>] ? bus_add_driver+0x1f1/0x290
   [<ffffffff81b37fa8>] ? uncore_cpu_setup+0xc/0xc
   [<ffffffff813da73f>] ? driver_register+0x5f/0xe0
   [<ffffffff81b38074>] ? intel_uncore_init+0xcc/0x2b0
   [<ffffffff81b37fa8>] ? uncore_cpu_setup+0xc/0xc
   [<ffffffff8100213e>] ? do_one_initcall+0xce/0x200
   [<ffffffff8108a100>] ? parse_args+0x140/0x4e0
   [<ffffffff81b2b0cb>] ? kernel_init_freeable+0x162/0x1e8
   [<ffffffff815443f0>] ? rest_init+0x80/0x80
   [<ffffffff815443fe>] ? kernel_init+0xe/0xf0
   [<ffffffff81553e5f>] ? ret_from_fork+0x3f/0x70
   [<ffffffff815443f0>] ? rest_init+0x80/0x80
  ---[ end trace 472e7959536abf12 ]---

00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge -OPI (rev 09)
Subsystem: Lenovo Device 2223
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx-
Latency: 0
Capabilities: [e0] Vendor Specific Information: Len=0c <?>
Kernel driver in use: bdw_uncore
00: 86 80 04 16 06 00 90 20 09 00 00 06 00 00 00 00
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 aa 17 23 22
30: 00 00 00 00 e0 00 00 00 00 00 00 00 00 00 00 00

---
 drivers/pnp/quirks.c |    1 +
 1 file changed, 1 insertion(+)

@@ -344,6 +344,7 @@ static const unsigned int mch_quirk_devi
 	0x0154,	/* Ivy Bridge */
 	0x0a04, /* Haswell-ULT */
 	0x0c00,	/* Haswell */
+	0x1604, /* Broadwell */
 };
 
 static struct pci_dev *get_intel_host(void)

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Benjamin Tissoires <[email protected]>

commit 19f4c2ba869517048add62c202f9645b6adf5dfb upstream.

When setting the operational mode, some third party (Speedlink Strike-FX) gamepads refuse the output report. Failing here means we refuse to initialize the gamepad while this should be harmless.

The weird part is that the initial commit that added this: a7de9b8 ("HID: sony: Enable Gasia third-party PS3 controllers") mentions this very same controller as one requiring this output report. Anyway, it's broken for one user at least, so let's change it. We will report an error, but at least the controller should work.

And no, these devices present themselves as legacy Sony controllers (VID:PID of 054C:0268, as in the official ones) so there are no ways of discriminating them from the official ones.

https://bugzilla.redhat.com/show_bug.cgi?id=1255325

---
 drivers/hid/hid-sony.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -1418,8 +1418,10 @@ static int sixaxis_set_operational_usb(s
 	}
 
 	ret = hid_hw_output_report(hdev, buf, 1);
-	if (ret < 0)
-		hid_err(hdev, "can't set operational mode: step 3\n");
+	if (ret < 0) {
+		hid_info(hdev, "can't set operational mode: step 3, ignoring\n");
+		ret = 0;
+	}
 
 out:
 	kfree(buf);

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hector Marco-Gisbert <[email protected]>

commit 8b8addf891de8a00e4d39fc32f93f7c5eb8feceb upstream.

Currently on i386 and on X86_64 when emulating X86_32 in legacy mode, only the stack and the executable are randomized but not other mmapped files (libraries, vDSO, etc.). This patch enables randomization for the libraries, vDSO and mmap requests on i386 and in X86_32 in legacy mode.

By default on i386 there are 8 bits for the randomization of the libraries, vDSO and mmaps which only uses 1MB of VA.

This patch preserves the original randomness, using 1MB of VA out of 3GB or 4GB. We think that 1MB out of 3GB is not a big cost for having the ASLR.

The first obvious security benefit is that all objects are randomized (not only the stack and the executable) in legacy mode which highly increases the ASLR effectiveness, otherwise the attackers may use these non-randomized areas. But also sensitive setuid/setgid applications are more secure because currently, attackers can disable the randomization of these applications by setting the ulimit stack to "unlimited". This is a very old and widely known trick to disable the ASLR in i386 which has been allowed for too long.

Another trick used to disable the ASLR was to set the ADDR_NO_RANDOMIZE personality flag, but fortunately this doesn't work on setuid/setgid applications because there is security checks which clear Security-relevant flags.

This patch always randomizes the mmap_legacy_base address, removing the possibility to disable the ASLR by setting the stack to "unlimited".

---
 arch/x86/mm/mmap.c |   14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

@@ -94,18 +94,6 @@ static unsigned long mmap_base(unsigned
 }
 
 /*
- * Bottom-up (legacy) layout on X86_32 did not support randomization, X86_64
- * does, but not when emulating X86_32
- */
-static unsigned long mmap_legacy_base(unsigned long rnd)
-{
-	if (mmap_is_ia32())
-		return TASK_UNMAPPED_BASE;
-	else
-		return TASK_UNMAPPED_BASE + rnd;
-}
-
-/*
  * This function, called very early during the creation of a new
  * process VM image, sets up which VM layout function to use:
  */

@@ -116,7 +104,7 @@ void arch_pick_mmap_layout(struct mm_str
 	if (current->flags & PF_RANDOMIZE)
 		random_factor = arch_mmap_rnd();
 
-	mm->mmap_legacy_base = mmap_legacy_base(random_factor);
+	mm->mmap_legacy_base = TASK_UNMAPPED_BASE + random_factor;
 
 	if (mmap_is_legacy()) {
 		mm->mmap_base = mm->mmap_legacy_base;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dave Weinstein <[email protected]>

commit 7de249964f5578e67b99699c5f0b405738d820a2 upstream.

Add access checks to sys_oabi_epoll_wait() and sys_oabi_semtimedop(). This fixes CVE-2016-3857, a local privilege escalation under CONFIG_OABI_COMPAT.

---
 arch/arm/kernel/sys_oabi-compat.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

@@ -279,8 +279,12 @@ asmlinkage long sys_oabi_epoll_wait(int
 	mm_segment_t fs;
 	long ret, err, i;
 
-	if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event)))
+	if (maxevents <= 0 ||
+			maxevents > (INT_MAX/sizeof(*kbuf)) ||
+			maxevents > (INT_MAX/sizeof(*events)))
 		return -EINVAL;
+	if (!access_ok(VERIFY_WRITE, events, sizeof(*events) * maxevents))
+		return -EFAULT;
 	kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL);
 	if (!kbuf)
 		return -ENOMEM;

@@ -317,6 +321,8 @@ asmlinkage long sys_oabi_semtimedop(int
 
 	if (nsops < 1 || nsops > SEMOPM)
 		return -EINVAL;
+	if (!access_ok(VERIFY_READ, tsops, sizeof(*tsops) * nsops))
+		return -EFAULT;
 	sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL);
 	if (!sops)
 		return -ENOMEM;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: David Howells <[email protected]>

commit 20f06ed9f61a185c6dabd662c310bed6189470df upstream.

MIPS64 needs to use compat_sys_keyctl for 32-bit userspace rather than calling sys_keyctl. The latter will work in a lot of cases, thereby hiding the issue.

Patchwork: https://patchwork.linux-mips.org/patch/13832/

---
 arch/mips/kernel/scall64-n32.S |    2 +-
 arch/mips/kernel/scall64-o32.S |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

@@ -344,7 +344,7 @@ EXPORT(sysn32_call_table)
 	PTR	sys_ni_syscall			/* available, was setaltroot */
 	PTR	sys_add_key
 	PTR	sys_request_key
-	PTR	sys_keyctl			/* 6245 */
+	PTR	compat_sys_keyctl		/* 6245 */
 	PTR	sys_set_thread_area
 	PTR	sys_inotify_init
 	PTR	sys_inotify_add_watch

@@ -500,7 +500,7 @@ EXPORT(sys32_call_table)
 	PTR	sys_ni_syscall			/* available, was setaltroot */
 	PTR	sys_add_key			/* 4280 */
 	PTR	sys_request_key
-	PTR	sys_keyctl
+	PTR	compat_sys_keyctl
 	PTR	sys_set_thread_area
 	PTR	sys_inotify_init
 	PTR	sys_inotify_add_watch		/* 4285 */

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Michael Holzheu <[email protected]>

commit 5419447e2142d6ed68c9f5c1a28630b3a290a845 upstream.

This reverts commit 852ffd0f4e23248b47531058e531066a988434b5.

There are use cases where an intermediate boot kernel (1) uses kexec to boot the final production kernel (2). For this scenario we should provide the original boot information to the production kernel (2). Therefore clearing the boot information during kexec() should not be done.

---
 arch/s390/kernel/ipl.c |    7 -------
 1 file changed, 7 deletions(-)

@@ -2070,13 +2070,6 @@ void s390_reset_system(void (*fn_pre)(vo
 	S390_lowcore.program_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) s390_base_pgm_handler;
 
-	/*
-	 * Clear subchannel ID and number to signal new kernel that no CCW or
-	 * SCSI IPL has been done (for kexec and kdump)
-	 */
-	S390_lowcore.subchannel_id = 0;
-	S390_lowcore.subchannel_nr = 0;
-
 	/* Store status at absolute zero */
 	store_status();
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: John Johansen <[email protected]>

commit 0b938a2e2cf0b0a2c8bac9769111545aff0fee97 upstream.

---
 security/apparmor/apparmorfs.c |    1 +
 1 file changed, 1 insertion(+)

@@ -331,6 +331,7 @@ static int aa_fs_seq_hash_show(struct se
 			seq_printf(seq, "%.2x", profile->hash[i]);
 		seq_puts(seq, "\n");
 	}
+	aa_put_profile(profile);
 
 	return 0;
 }

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Theodore Ts'o <[email protected]>

commit 86a574de4590ffe6fd3f3ca34cdcf655a78e36ec upstream.

Don't allow RNDADDTOENTCNT or RNDADDENTROPY to accept a negative entropy value. It doesn't make any sense to subtract from the entropy counter, and it can trigger a warning:

random: negative entropy/overflow: pool input count -40000

------------[ cut here ]------------
WARNING: CPU: 3 PID: 6828 at drivers/char/random.c:670[<      none
 >] credit_entropy_bits+0x21e/0xad0 drivers/char/random.c:670
Modules linked in:
CPU: 3 PID: 6828 Comm: a.out Not tainted 4.7.0-rc4+ #4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 ffffffff880b58e0 ffff88005dd9fcb0 ffffffff82cc838f ffffffff87158b40
 fffffbfff1016b1c 0000000000000000 0000000000000000 ffffffff87158b40
 ffffffff83283dae 0000000000000009 ffff88005dd9fcf8 ffffffff8136d27f
Call Trace:
 [<     inline     >] __dump_stack lib/dump_stack.c:15
 [<ffffffff82cc838f>] dump_stack+0x12e/0x18f lib/dump_stack.c:51
 [<ffffffff8136d27f>] __warn+0x19f/0x1e0 kernel/panic.c:516
 [<ffffffff8136d48c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:551
 [<ffffffff83283dae>] credit_entropy_bits+0x21e/0xad0 drivers/char/random.c:670
 [<     inline     >] credit_entropy_bits_safe drivers/char/random.c:734
 [<ffffffff8328785d>] random_ioctl+0x21d/0x250 drivers/char/random.c:1546
 [<     inline     >] vfs_ioctl fs/ioctl.c:43
 [<ffffffff8185316c>] do_vfs_ioctl+0x18c/0xff0 fs/ioctl.c:674
 [<     inline     >] SYSC_ioctl fs/ioctl.c:689
 [<ffffffff8185405f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
 [<ffffffff86a995c0>] entry_SYSCALL_64_fastpath+0x23/0xc1
arch/x86/entry/entry_64.S:207
---[ end trace 5d4902b2ba842f1f ]---

This was triggered using the test program:

// autogenerated by syzkaller (http://github.com/google/syzkaller)

int main() {
        int fd = open("/dev/random", O_RDWR);
        int val = -5000;
        ioctl(fd, RNDADDTOENTCNT, &val);
        return 0;
}

It's harmless in that (a) only root can trigger it, and (b) after complaining the code never does let the entropy count go negative, but it's better to simply not allow this userspace from passing in a negative entropy value altogether.

Google-Bug-Id: #29575089

---
 drivers/char/random.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

@@ -722,15 +722,18 @@ retry:
 	}
 }
 
-static void credit_entropy_bits_safe(struct entropy_store *r, int nbits)
+static int credit_entropy_bits_safe(struct entropy_store *r, int nbits)
 {
 	const int nbits_max = (int)(~0U >> (ENTROPY_SHIFT + 1));
 
+	if (nbits < 0)
+		return -EINVAL;
+
 	/* Cap the value to avoid overflows */
 	nbits = min(nbits,  nbits_max);
-	nbits = max(nbits, -nbits_max);
 
 	credit_entropy_bits(r, nbits);
+	return 0;
 }
 
 /*********************************************************************

@@ -1542,8 +1545,7 @@ static long random_ioctl(struct file *f,
 			return -EPERM;
 		if (get_user(ent_count, p))
 			return -EFAULT;
-		credit_entropy_bits_safe(&input_pool, ent_count);
-		return 0;
+		return credit_entropy_bits_safe(&input_pool, ent_count);
 	case RNDADDENTROPY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;

@@ -1557,8 +1559,7 @@ static long random_ioctl(struct file *f,
 				    size);
 		if (retval < 0)
 			return retval;
-		credit_entropy_bits_safe(&input_pool, ent_count);
-		return 0;
+		return credit_entropy_bits_safe(&input_pool, ent_count);
 	case RNDZAPENTCNT:
 	case RNDCLEARPOOL:
 		/*

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Linus Torvalds <[email protected]>

commit 67245ff332064c01b760afa7a384ccda024bfd24 upstream.

This gets rid of the horrible notion of having that

struct inode *ptmx_inode

be the linchpin of the interface between the pty code and devpts.

By de-emphasizing the ptmx inode, a lot of things actually get cleaner, and we will have a much saner way forward. In particular, this will allow us to associate with any particular devpts instance at open-time, and not be artificially tied to one particular ptmx inode.

The patch itself is actually fairly straightforward, and apart from some locking and return path cleanups it's pretty mechanical:

- the interfaces that devpts exposes all take "struct pts_fs_info *" instead of "struct inode *ptmx_inode" now.

NOTE! The "struct pts_fs_info" thing is a completely opaque structure as far as the pty driver is concerned: it's still declared entirely internally to devpts. So the pty code can't actually access it in any way, just pass it as a "cookie" to the devpts code.

- the "look up the pts fs info" is now a single clear operation, that also does the reference count increment on the pts superblock.

So "devpts_add/del_ref()" is gone, and replaced by a "lookup and get ref" operation (devpts_get_ref(inode)), along with a "put ref" op (devpts_put_ref()).

- the pty master "tty->driver_data" field now contains the pts_fs_info, not the ptmx inode.

- because we don't care about the ptmx inode any more as some kind of base index, the ref counting can now drop the inode games - it just gets the ref on the superblock.

- the pts_fs_info now has a back-pointer to the super_block. That's so that we can easily look up the information we actually need. Although quite often, the pts fs info was actually all we wanted, and not having to look it up based on some magical inode makes things more straightforward.

In particular, now that "devpts_get_ref(inode)" operation should really be the *only* place we need to look up what devpts instance we're associated with, and we do it exactly once, at ptmx_open() time.

The other side of this is that one ptmx node could now be associated with multiple different devpts instances - you could have a single /dev/ptmx node, and then have multiple mount namespaces with their own instances of devpts mounted on /dev/pts/. And that's all perfectly sane in a model where we just look up the pts instance at open time.

This will eventually allow us to get rid of our odd single-vs-multiple pts instance model, but this patch in itself changes no semantics, only an internal binding model.

---
 drivers/tty/pty.c         |   63 +++++++++++++++++++++-------------------------
 fs/devpts/inode.c         |   49 +++++++++++++++++------------------
 include/linux/devpts_fs.h |   34 +++++++-----------------
 3 files changed, 64 insertions(+), 82 deletions(-)

@@ -679,14 +679,14 @@ static void pty_unix98_remove(struct tty
 /* this is called once with whichever end is closed last */
 static void pty_unix98_shutdown(struct tty_struct *tty)
 {
-	struct inode *ptmx_inode;
+	struct pts_fs_info *fsi;
 
 	if (tty->driver->subtype == PTY_TYPE_MASTER)
-		ptmx_inode = tty->driver_data;
+		fsi = tty->driver_data;
 	else
-		ptmx_inode = tty->link->driver_data;
-	devpts_kill_index(ptmx_inode, tty->index);
-	devpts_del_ref(ptmx_inode);
+		fsi = tty->link->driver_data;
+	devpts_kill_index(fsi, tty->index);
+	devpts_put_ref(fsi);
 }
 
 static const struct tty_operations ptm_unix98_ops = {

@@ -738,6 +738,7 @@ static const struct tty_operations pty_u
 
 static int ptmx_open(struct inode *inode, struct file *filp)
 {
+	struct pts_fs_info *fsi;
 	struct tty_struct *tty;
 	struct inode *slave_inode;
 	int retval;

@@ -752,47 +753,41 @@ static int ptmx_open(struct inode *inode
 	if (retval)
 		return retval;
 
+	fsi = devpts_get_ref(inode, filp);
+	retval = -ENODEV;
+	if (!fsi)
+		goto out_free_file;
+
 	/* find a device that is not in use. */
 	mutex_lock(&devpts_mutex);
-	index = devpts_new_index(inode);
-	if (index < 0) {
-		retval = index;
-		mutex_unlock(&devpts_mutex);
-		goto err_file;
-	}
-
+	index = devpts_new_index(fsi);
 	mutex_unlock(&devpts_mutex);
 
-	mutex_lock(&tty_mutex);
-	tty = tty_init_dev(ptm_driver, index);
+	retval = index;
+	if (index < 0)
+		goto out_put_ref;
 
-	if (IS_ERR(tty)) {
-		retval = PTR_ERR(tty);
-		goto out;
-	}
 
+	mutex_lock(&tty_mutex);
+	tty = tty_init_dev(ptm_driver, index);
 	/* The tty returned here is locked so we can safely
 	   drop the mutex */
 	mutex_unlock(&tty_mutex);
 
-	set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
-	tty->driver_data = inode;
+	retval = PTR_ERR(tty);
+	if (IS_ERR(tty))
+		goto out;
 
 	/*
-	 * In the case where all references to ptmx inode are dropped and we
-	 * still have /dev/tty opened pointing to the master/slave pair (ptmx
-	 * is closed/released before /dev/tty), we must make sure that the inode
-	 * is still valid when we call the final pty_unix98_shutdown, thus we
-	 * hold an additional reference to the ptmx inode. For the same /dev/tty
-	 * last close case, we also need to make sure the super_block isn't
-	 * destroyed (devpts instance unmounted), before /dev/tty is closed and
-	 * on its release devpts_kill_index is called.
+	 * From here on out, the tty is "live", and the index and
+	 * fsi will be killed/put by the tty_release()
 	 */
-	devpts_add_ref(inode);
+	set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
+	tty->driver_data = fsi;
 
 	tty_add_file(tty, filp);
 
-	slave_inode = devpts_pty_new(inode,
+	slave_inode = devpts_pty_new(fsi,
 			MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
 			tty->link);
 	if (IS_ERR(slave_inode)) {

@@ -811,12 +806,14 @@ static int ptmx_open(struct inode *inode
 	return 0;
 err_release:
 	tty_unlock(tty);
+	// This will also put-ref the fsi
 	tty_release(inode, filp);
 	return retval;
 out:
-	mutex_unlock(&tty_mutex);
-	devpts_kill_index(inode, index);
-err_file:
+	devpts_kill_index(fsi, index);
+out_put_ref:
+	devpts_put_ref(fsi);
+out_free_file:
 	tty_free_file(filp);
 	return retval;
 }

@@ -15,38 +15,24 @@
 
 #include <linux/errno.h>
 
+struct pts_fs_info;
+
 #ifdef CONFIG_UNIX98_PTYS
 
-int devpts_new_index(struct inode *ptmx_inode);
-void devpts_kill_index(struct inode *ptmx_inode, int idx);
-void devpts_add_ref(struct inode *ptmx_inode);
-void devpts_del_ref(struct inode *ptmx_inode);
+/* Look up a pts fs info and get a ref to it */
+struct pts_fs_info *devpts_get_ref(struct inode *, struct file *);
+void devpts_put_ref(struct pts_fs_info *);
+
+int devpts_new_index(struct pts_fs_info *);
+void devpts_kill_index(struct pts_fs_info *, int);
+
 /* mknod in devpts */
-struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
-		void *priv);
+struct inode *devpts_pty_new(struct pts_fs_info *, dev_t, int, void *);
 /* get private structure */
 void *devpts_get_priv(struct inode *pts_inode);
 /* unlink */
 void devpts_pty_kill(struct inode *inode);
 
-#else
-
-/* Dummy stubs in the no-pty case */
-static inline int devpts_new_index(struct inode *ptmx_inode) { return -EINVAL; }
-static inline void devpts_kill_index(struct inode *ptmx_inode, int idx) { }
-static inline void devpts_add_ref(struct inode *ptmx_inode) { }
-static inline void devpts_del_ref(struct inode *ptmx_inode) { }
-static inline struct inode *devpts_pty_new(struct inode *ptmx_inode,
-		dev_t device, int index, void *priv)
-{
-	return ERR_PTR(-EINVAL);
-}
-static inline void *devpts_get_priv(struct inode *pts_inode)
-{
-	return NULL;
-}
-static inline void devpts_pty_kill(struct inode *inode) { }
-
 #endif
 
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit 02f037d641dc6672be5cfe7875a48ab99b95b154 upstream.

In preparation for fixing a regression caused by:

9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled")'

... PAT needs to support a case that PAT MSR is initialized with a non-default value.

When pat_init() is called and PAT is disabled, it initializes the PAT table with the BIOS default value. Xen, however, sets PAT MSR with a non-default value to enable WC. This causes inconsistency between the PAT table and PAT MSR when PAT is set to disable on Xen.

Change pat_init() to handle the PAT disable cases properly. Add init_cache_modes() to handle two cases when PAT is set to disable.

1. CPU supports PAT: Set PAT table to be consistent with PAT MSR.
2. CPU does not support PAT: Set PAT table to be consistent with PWT and PCD bits in a PTE.

Note, __init_cache_modes(), renamed from pat_init_cache_modes(), will be changed to a static function in a later patch.

---
 arch/x86/include/asm/pat.h |    2 -
 arch/x86/mm/pat.c          |   73 ++++++++++++++++++++++++++++++++-------------
 arch/x86/xen/enlighten.c   |    2 -
 3 files changed, 55 insertions(+), 22 deletions(-)

@@ -6,7 +6,7 @@
 
 bool pat_enabled(void);
 extern void pat_init(void);
-void pat_init_cache_modes(u64);
+void __init_cache_modes(u64);
 
 extern int reserve_memtype(u64 start, u64 end,
 		enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm);

@@ -1632,7 +1632,7 @@ asmlinkage __visible void __init xen_sta
 	 * configuration.
 	 */
 	rdmsrl(MSR_IA32_CR_PAT, pat);
-	pat_init_cache_modes(pat);
+	__init_cache_modes(pat);
 
 	/* keep using Xen gdt for now; no urgent need to change it */
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit 02f037d641dc6672be5cfe7875a48ab99b95b154 upstream.

In preparation for fixing a regression caused by:

9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled")'

... PAT needs to support a case that PAT MSR is initialized with a non-default value.

When pat_init() is called and PAT is disabled, it initializes the PAT table with the BIOS default value. Xen, however, sets PAT MSR with a non-default value to enable WC. This causes inconsistency between the PAT table and PAT MSR when PAT is set to disable on Xen.

Change pat_init() to handle the PAT disable cases properly. Add init_cache_modes() to handle two cases when PAT is set to disable.

1. CPU supports PAT: Set PAT table to be consistent with PAT MSR.
2. CPU does not support PAT: Set PAT table to be consistent with PWT and PCD bits in a PTE.

Note, __init_cache_modes(), renamed from pat_init_cache_modes(), will be changed to a static function in a later patch.

---
 arch/x86/include/asm/pat.h |    2 -
 arch/x86/mm/pat.c          |   73 ++++++++++++++++++++++++++++++++-------------
 arch/x86/xen/enlighten.c   |    2 -
 3 files changed, 55 insertions(+), 22 deletions(-)

@@ -6,7 +6,7 @@
 
 bool pat_enabled(void);
 extern void pat_init(void);
-void pat_init_cache_modes(u64);
+void __init_cache_modes(u64);
 
 extern int reserve_memtype(u64 start, u64 end,
 		enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm);

@@ -1632,7 +1632,7 @@ asmlinkage __visible void __init xen_sta
 	 * configuration.
 	 */
 	rdmsrl(MSR_IA32_CR_PAT, pat);
-	pat_init_cache_modes(pat);
+	__init_cache_modes(pat);
 
 	/* keep using Xen gdt for now; no urgent need to change it */
 

_______________________________________________
Xen-devel mailing list
[email protected]
https://lists.xen.org/xen-devel

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit 224bb1e5d67ba0f2872c98002d6a6f991ac6fd4a upstream.

In preparation for fixing a regression caused by:

9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled")

... PAT needs to provide an interface that prevents the OS from initializing the PAT MSR.

PAT MSR initialization must be done on all CPUs using the specific sequence of operations defined in the Intel SDM. This requires MTRRs to be enabled since pat_init() is called as part of MTRR init from mtrr_rendezvous_handler().

Make pat_disable() as the interface that prevents the OS from initializing the PAT MSR. MTRR will call this interface when it cannot provide the SDM-defined sequence to initialize PAT.

This also assures that pat_disable() called from pat_bsp_init() will set the PAT table properly when CPU does not support PAT.

---
 arch/x86/include/asm/pat.h |    1 +
 arch/x86/mm/pat.c          |   13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

@@ -5,6 +5,7 @@
 #include <asm/pgtable_types.h>
 
 bool pat_enabled(void);
+void pat_disable(const char *reason);
 extern void pat_init(void);
 void __init_cache_modes(u64);
 

@@ -39,11 +39,22 @@
 static bool boot_cpu_done;
 
 static int __read_mostly __pat_enabled = IS_ENABLED(CONFIG_X86_PAT);
+static void init_cache_modes(void);
 
-static inline void pat_disable(const char *reason)
+void pat_disable(const char *reason)
 {
+	if (!__pat_enabled)
+		return;
+
+	if (boot_cpu_done) {
+		WARN_ONCE(1, "x86/PAT: PAT cannot be disabled after initialization\n");
+		return;
+	}
+
 	__pat_enabled = 0;
 	pr_info("x86/PAT: %s\n", reason);
+
+	init_cache_modes();
 }
 
 static int __init nopat(char *str)

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit 224bb1e5d67ba0f2872c98002d6a6f991ac6fd4a upstream.

In preparation for fixing a regression caused by:

9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled")

... PAT needs to provide an interface that prevents the OS from initializing the PAT MSR.

PAT MSR initialization must be done on all CPUs using the specific sequence of operations defined in the Intel SDM. This requires MTRRs to be enabled since pat_init() is called as part of MTRR init from mtrr_rendezvous_handler().

Make pat_disable() as the interface that prevents the OS from initializing the PAT MSR. MTRR will call this interface when it cannot provide the SDM-defined sequence to initialize PAT.

This also assures that pat_disable() called from pat_bsp_init() will set the PAT table properly when CPU does not support PAT.

---
 arch/x86/include/asm/pat.h |    1 +
 arch/x86/mm/pat.c          |   13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

@@ -5,6 +5,7 @@
 #include <asm/pgtable_types.h>
 
 bool pat_enabled(void);
+void pat_disable(const char *reason);
 extern void pat_init(void);
 void __init_cache_modes(u64);
 

@@ -39,11 +39,22 @@
 static bool boot_cpu_done;
 
 static int __read_mostly __pat_enabled = IS_ENABLED(CONFIG_X86_PAT);
+static void init_cache_modes(void);
 
-static inline void pat_disable(const char *reason)
+void pat_disable(const char *reason)
 {
+	if (!__pat_enabled)
+		return;
+
+	if (boot_cpu_done) {
+		WARN_ONCE(1, "x86/PAT: PAT cannot be disabled after initialization\n");
+		return;
+	}
+
 	__pat_enabled = 0;
 	pr_info("x86/PAT: %s\n", reason);
+
+	init_cache_modes();
 }
 
 static int __init nopat(char *str)

_______________________________________________
Xen-devel mailing list
[email protected]
https://lists.xen.org/xen-devel

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit d63dcf49cf5ae5605f4d14229e3888e104f294b1 upstream.

Borislav Petkov suggested:

Replace the use of cpu_has_pat on init paths with boot_cpu_has().

---
 arch/x86/mm/pat.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -212,7 +212,7 @@ static void pat_bsp_init(u64 pat)
 {
 	u64 tmp_pat;
 
-	if (!cpu_has_pat) {
+	if (!boot_cpu_has(X86_FEATURE_PAT)) {
 		pat_disable("PAT not supported by CPU.");
 		return;
 	}

@@ -230,7 +230,7 @@ static void pat_bsp_init(u64 pat)
 
 static void pat_ap_init(u64 pat)
 {
-	if (!cpu_has_pat) {
+	if (!boot_cpu_has(X86_FEATURE_PAT)) {
 		/*
 		 * If this happens we are on a secondary CPU, but switched to
 		 * PAT on the boot CPU. We have no way to undo PAT.

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit d63dcf49cf5ae5605f4d14229e3888e104f294b1 upstream.

Borislav Petkov suggested:

Replace the use of cpu_has_pat on init paths with boot_cpu_has().

---
 arch/x86/mm/pat.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -212,7 +212,7 @@ static void pat_bsp_init(u64 pat)
 {
 	u64 tmp_pat;
 
-	if (!cpu_has_pat) {
+	if (!boot_cpu_has(X86_FEATURE_PAT)) {
 		pat_disable("PAT not supported by CPU.");
 		return;
 	}

@@ -230,7 +230,7 @@ static void pat_bsp_init(u64 pat)
 
 static void pat_ap_init(u64 pat)
 {
-	if (!cpu_has_pat) {
+	if (!boot_cpu_has(X86_FEATURE_PAT)) {
 		/*
 		 * If this happens we are on a secondary CPU, but switched to
 		 * PAT on the boot CPU. We have no way to undo PAT.

_______________________________________________
Xen-devel mailing list
[email protected]
https://lists.xen.org/xen-devel

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit edfe63ec97ed8d4496225f7ba54c9ce4207c5431 upstream.

A Xorg failure on qemu32 was reported as a regression [1] caused by commit 9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled").

This patch fixes the Xorg crash.

Negative effects of this regression were the following two failures [2] in Xorg on QEMU with QEMU CPU model "qemu32" (-cpu qemu32), which were triggered by the fact that its virtual CPU does not support MTRRs.

#1. copy_process() failed in the check in reserve_pfn_range()

copy_process
copy_mm
dup_mm
dup_mmap
copy_page_range
track_pfn_copy
reserve_pfn_range

A WC map request was tracked as WC in memtype, which set a PTE as UC (pgprot) per __cachemode2pte_tbl[]. This led to this error in reserve_pfn_range() called from track_pfn_copy(), which obtained a pgprot from a PTE. It converts pgprot to page_cache_mode, which does not necessarily result in the original page_cache_mode since __cachemode2pte_tbl[] redirects multiple types to UC.

#2. error path in copy_process() then hit WARN_ON_ONCE in

     untrack_pfn().

     x86/PAT: Xorg:509 map pfn expected mapping type uncached-
     minus for [mem 0xfd000000-0xfdffffff], got write-combining
      Call Trace:
     dump_stack
     warn_slowpath_common
     ? untrack_pfn
     ? untrack_pfn
     warn_slowpath_null
     untrack_pfn
     ? __kunmap_atomic
     unmap_single_vma
     ? pagevec_move_tail_fn
     unmap_vmas
     exit_mmap
     mmput
     copy_process.part.47
     _do_fork
     SyS_clone
     do_syscall_32_irqs_on
     entry_INT80_32

These negative effects are caused by two separate bugs, but they can be addressed in separate patches. Fixing the pat_init() issue described below addresses the root cause, and avoids Xorg to hit these cases.

When the CPU does not support MTRRs, MTRR does not call pat_init(), which leaves PAT enabled without initializing PAT. This pat_init() issue is a long-standing issue, but manifested as issue #1 (and then hit issue #2) with the above-mentioned commit because the memtype now tracks cache attribute with 'page_cache_mode'.

This pat_init() issue existed before the commit, but we used pgprot in memtype. Hence, we did not have issue #1 before. But WC request resulted in WT in effect because WC pgrot is actually WT when PAT is not initialized. This is not how it was designed to work. When PAT is set to disable properly, WC is converted to UC. The use of WT can result in a system crash if the target range does not support WT. Fortunately, nobody ran into such issue before.

To fix this pat_init() issue, PAT code has been enhanced to provide pat_disable() interface. Call this interface when MTRRs are disabled. By setting PAT to disable properly, PAT bypasses the memtype check, and avoids issue #1.

[1]: https://lkml.org/lkml/2016/3/3/828
[2]: https://lkml.org/lkml/2016/3/4/775

---
 arch/x86/include/asm/mtrr.h     |    6 +++++-
 arch/x86/kernel/cpu/mtrr/main.c |   10 +++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

@@ -24,6 +24,7 @@
 #define _ASM_X86_MTRR_H
 
 #include <uapi/asm/mtrr.h>
+#include <asm/pat.h>
 
 
 /*

@@ -83,9 +84,12 @@ static inline int mtrr_trim_uncached_mem
 static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
 {
 }
+static inline void mtrr_bp_init(void)
+{
+	pat_disable("MTRRs disabled, skipping PAT initialization too.");
+}
 
 #define mtrr_ap_init() do {} while (0)
-#define mtrr_bp_init() do {} while (0)
 #define set_mtrr_aps_delayed_init() do {} while (0)
 #define mtrr_aps_init() do {} while (0)
 #define mtrr_bp_restore() do {} while (0)

@@ -759,8 +759,16 @@ void __init mtrr_bp_init(void)
 		}
 	}
 
-	if (!mtrr_enabled())
+	if (!mtrr_enabled()) {
 		pr_info("MTRR: Disabled\n");
+
+		/*
+		 * PAT initialization relies on MTRR's rendezvous handler.
+		 * Skip PAT init until the handler can initialize both
+		 * features independently.
+		 */
+		pat_disable("MTRRs disabled, skipping PAT initialization too.");
+	}
 }
 
 void mtrr_ap_init(void)

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit edfe63ec97ed8d4496225f7ba54c9ce4207c5431 upstream.

A Xorg failure on qemu32 was reported as a regression [1] caused by commit 9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled").

This patch fixes the Xorg crash.

Negative effects of this regression were the following two failures [2] in Xorg on QEMU with QEMU CPU model "qemu32" (-cpu qemu32), which were triggered by the fact that its virtual CPU does not support MTRRs.

#1. copy_process() failed in the check in reserve_pfn_range()

copy_process
copy_mm
dup_mm
dup_mmap
copy_page_range
track_pfn_copy
reserve_pfn_range

A WC map request was tracked as WC in memtype, which set a PTE as UC (pgprot) per __cachemode2pte_tbl[]. This led to this error in reserve_pfn_range() called from track_pfn_copy(), which obtained a pgprot from a PTE. It converts pgprot to page_cache_mode, which does not necessarily result in the original page_cache_mode since __cachemode2pte_tbl[] redirects multiple types to UC.

#2. error path in copy_process() then hit WARN_ON_ONCE in

     untrack_pfn().

     x86/PAT: Xorg:509 map pfn expected mapping type uncached-
     minus for [mem 0xfd000000-0xfdffffff], got write-combining
      Call Trace:
     dump_stack
     warn_slowpath_common
     ? untrack_pfn
     ? untrack_pfn
     warn_slowpath_null
     untrack_pfn
     ? __kunmap_atomic
     unmap_single_vma
     ? pagevec_move_tail_fn
     unmap_vmas
     exit_mmap
     mmput
     copy_process.part.47
     _do_fork
     SyS_clone
     do_syscall_32_irqs_on
     entry_INT80_32

These negative effects are caused by two separate bugs, but they can be addressed in separate patches. Fixing the pat_init() issue described below addresses the root cause, and avoids Xorg to hit these cases.

When the CPU does not support MTRRs, MTRR does not call pat_init(), which leaves PAT enabled without initializing PAT. This pat_init() issue is a long-standing issue, but manifested as issue #1 (and then hit issue #2) with the above-mentioned commit because the memtype now tracks cache attribute with 'page_cache_mode'.

This pat_init() issue existed before the commit, but we used pgprot in memtype. Hence, we did not have issue #1 before. But WC request resulted in WT in effect because WC pgrot is actually WT when PAT is not initialized. This is not how it was designed to work. When PAT is set to disable properly, WC is converted to UC. The use of WT can result in a system crash if the target range does not support WT. Fortunately, nobody ran into such issue before.

To fix this pat_init() issue, PAT code has been enhanced to provide pat_disable() interface. Call this interface when MTRRs are disabled. By setting PAT to disable properly, PAT bypasses the memtype check, and avoids issue #1.

[1]: https://lkml.org/lkml/2016/3/3/828
[2]: https://lkml.org/lkml/2016/3/4/775

---
 arch/x86/include/asm/mtrr.h     |    6 +++++-
 arch/x86/kernel/cpu/mtrr/main.c |   10 +++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

@@ -24,6 +24,7 @@
 #define _ASM_X86_MTRR_H
 
 #include <uapi/asm/mtrr.h>
+#include <asm/pat.h>
 
 
 /*

@@ -83,9 +84,12 @@ static inline int mtrr_trim_uncached_mem
 static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
 {
 }
+static inline void mtrr_bp_init(void)
+{
+	pat_disable("MTRRs disabled, skipping PAT initialization too.");
+}
 
 #define mtrr_ap_init() do {} while (0)
-#define mtrr_bp_init() do {} while (0)
 #define set_mtrr_aps_delayed_init() do {} while (0)
 #define mtrr_aps_init() do {} while (0)
 #define mtrr_bp_restore() do {} while (0)

@@ -759,8 +759,16 @@ void __init mtrr_bp_init(void)
 		}
 	}
 
-	if (!mtrr_enabled())
+	if (!mtrr_enabled()) {
 		pr_info("MTRR: Disabled\n");
+
+		/*
+		 * PAT initialization relies on MTRR's rendezvous handler.
+		 * Skip PAT init until the handler can initialize both
+		 * features independently.
+		 */
+		pat_disable("MTRRs disabled, skipping PAT initialization too.");
+	}
 }
 
 void mtrr_ap_init(void)

_______________________________________________
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[email protected]
https://lists.xen.org/xen-devel

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit ad025a73f0e9344ac73ffe1b74c184033e08e7d5 upstream.

get_mtrr_state() calls pat_init() on BSP even if MTRR is disabled. This results in calling pat_init() on BSP only since APs do not call pat_init() when MTRR is disabled. This inconsistency between BSP and APs leads to undefined behavior.

Make BSP's calling condition to pat_init() consistent with AP's, mtrr_ap_init() and mtrr_aps_init().

---
 arch/x86/kernel/cpu/mtrr/generic.c |   24 ++++++++++++++----------
 arch/x86/kernel/cpu/mtrr/main.c    |    3 +++
 arch/x86/kernel/cpu/mtrr/mtrr.h    |    1 +
 3 files changed, 18 insertions(+), 10 deletions(-)

@@ -444,11 +444,24 @@ static void __init print_mtrr_state(void
 		pr_debug("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);
 }
 
+/* PAT setup for BP. We need to go through sync steps here */
+void __init mtrr_bp_pat_init(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	prepare_set();
+
+	pat_init();
+
+	post_set();
+	local_irq_restore(flags);
+}
+
 /* Grab all of the MTRR state for this CPU into *state */
 bool __init get_mtrr_state(void)
 {
 	struct mtrr_var_range *vrs;
-	unsigned long flags;
 	unsigned lo, dummy;
 	unsigned int i;
 

@@ -481,15 +494,6 @@ bool __init get_mtrr_state(void)
 
 	mtrr_state_set = 1;
 
-	/* PAT setup for BP. We need to go through sync steps here */
-	local_irq_save(flags);
-	prepare_set();
-
-	pat_init();
-
-	post_set();
-	local_irq_restore(flags);
-
 	return !!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED);
 }
 

@@ -752,6 +752,9 @@ void __init mtrr_bp_init(void)
 			/* BIOS may override */
 			__mtrr_enabled = get_mtrr_state();
 
+			if (mtrr_enabled())
+				mtrr_bp_pat_init();
+
 			if (mtrr_cleanup(phys_addr)) {
 				changed_by_mtrr_cleanup = 1;
 				mtrr_if->set_all();

@@ -52,6 +52,7 @@ void set_mtrr_prepare_save(struct set_mt
 void fill_mtrr_var_range(unsigned int index,
 		u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi);
 bool get_mtrr_state(void);
+void mtrr_bp_pat_init(void);
 
 extern void set_mtrr_ops(const struct mtrr_ops *ops);
 

_______________________________________________
Xen-devel mailing list
[email protected]
https://lists.xen.org/xen-devel

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit 88ba281108ed0c25c9d292b48bd3f272fcb90dd0 upstream.

Xen supports PAT without MTRRs for its guests. In order to enable WC attribute, it was necessary for xen_start_kernel() to call pat_init_cache_modes() to update PAT table before starting guest kernel.

Now that the kernel initializes PAT table to the BIOS handoff state when MTRR is disabled, this Xen-specific PAT init code is no longer necessary. Delete it from xen_start_kernel().

Also change __init_cache_modes() to a static function since PAT table should not be tweaked by other modules.

---
 arch/x86/include/asm/pat.h |    1 -
 arch/x86/mm/pat.c          |    2 +-
 arch/x86/xen/enlighten.c   |    9 ---------
 3 files changed, 1 insertion(+), 11 deletions(-)

@@ -7,7 +7,6 @@
 bool pat_enabled(void);
 void pat_disable(const char *reason);
 extern void pat_init(void);
-void __init_cache_modes(u64);
 
 extern int reserve_memtype(u64 start, u64 end,
 		enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm);

@@ -191,7 +191,7 @@ static enum page_cache_mode pat_get_cach
  * configuration.
  * Using lower indices is preferred, so we start with highest index.
  */
-void __init_cache_modes(u64 pat)
+static void __init_cache_modes(u64 pat)
 {
 	enum page_cache_mode cache;
 	char pat_msg[33];

@@ -74,7 +74,6 @@
 #include <asm/mach_traps.h>
 #include <asm/mwait.h>
 #include <asm/pci_x86.h>
-#include <asm/pat.h>
 #include <asm/cpu.h>
 
 #ifdef CONFIG_ACPI

@@ -1519,7 +1518,6 @@ asmlinkage __visible void __init xen_sta
 {
 	struct physdev_set_iopl set_iopl;
 	unsigned long initrd_start = 0;
-	u64 pat;
 	int rc;
 
 	if (!xen_start_info)

@@ -1627,13 +1625,6 @@ asmlinkage __visible void __init xen_sta
 				   xen_start_info->nr_pages);
 	xen_reserve_special_pages();
 
-	/*
-	 * Modify the cache mode translation tables to match Xen's PAT
-	 * configuration.
-	 */
-	rdmsrl(MSR_IA32_CR_PAT, pat);
-	__init_cache_modes(pat);
-
 	/* keep using Xen gdt for now; no urgent need to change it */
 
 #ifdef CONFIG_X86_32

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit 88ba281108ed0c25c9d292b48bd3f272fcb90dd0 upstream.

Xen supports PAT without MTRRs for its guests. In order to enable WC attribute, it was necessary for xen_start_kernel() to call pat_init_cache_modes() to update PAT table before starting guest kernel.

Now that the kernel initializes PAT table to the BIOS handoff state when MTRR is disabled, this Xen-specific PAT init code is no longer necessary. Delete it from xen_start_kernel().

Also change __init_cache_modes() to a static function since PAT table should not be tweaked by other modules.

---
 arch/x86/include/asm/pat.h |    1 -
 arch/x86/mm/pat.c          |    2 +-
 arch/x86/xen/enlighten.c   |    9 ---------
 3 files changed, 1 insertion(+), 11 deletions(-)

@@ -7,7 +7,6 @@
 bool pat_enabled(void);
 void pat_disable(const char *reason);
 extern void pat_init(void);
-void __init_cache_modes(u64);
 
 extern int reserve_memtype(u64 start, u64 end,
 		enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm);

@@ -191,7 +191,7 @@ static enum page_cache_mode pat_get_cach
  * configuration.
  * Using lower indices is preferred, so we start with highest index.
  */
-void __init_cache_modes(u64 pat)
+static void __init_cache_modes(u64 pat)
 {
 	enum page_cache_mode cache;
 	char pat_msg[33];

@@ -74,7 +74,6 @@
 #include <asm/mach_traps.h>
 #include <asm/mwait.h>
 #include <asm/pci_x86.h>
-#include <asm/pat.h>
 #include <asm/cpu.h>
 
 #ifdef CONFIG_ACPI

@@ -1519,7 +1518,6 @@ asmlinkage __visible void __init xen_sta
 {
 	struct physdev_set_iopl set_iopl;
 	unsigned long initrd_start = 0;
-	u64 pat;
 	int rc;
 
 	if (!xen_start_info)

@@ -1627,13 +1625,6 @@ asmlinkage __visible void __init xen_sta
 				   xen_start_info->nr_pages);
 	xen_reserve_special_pages();
 
-	/*
-	 * Modify the cache mode translation tables to match Xen's PAT
-	 * configuration.
-	 */
-	rdmsrl(MSR_IA32_CR_PAT, pat);
-	__init_cache_modes(pat);
-
 	/* keep using Xen gdt for now; no urgent need to change it */
 
 #ifdef CONFIG_X86_32

_______________________________________________
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https://lists.xen.org/xen-devel

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit b6350c21cfe8aa9d65e189509a23c0ea4b8362c2 upstream.

Update PAT documentation to describe how PAT is initialized under various configurations.

---
 Documentation/x86/pat.txt |   32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

@@ -196,3 +196,35 @@ Another, more verbose way of getting PAT
 "debugpat" boot parameter. With this parameter, various debug messages are
 printed to dmesg log.
 
+PAT Initialization
+------------------
+
+The following table describes how PAT is initialized under various
+configurations. The PAT MSR must be updated by Linux in order to support WC
+and WT attributes. Otherwise, the PAT MSR has the value programmed in it
+by the firmware. Note, Xen enables WC attribute in the PAT MSR for guests.
+
+ MTRR PAT   Call Sequence               PAT State  PAT MSR
+ =========================================================
+ E    E     MTRR -> PAT init            Enabled    OS
+ E    D     MTRR -> PAT init            Disabled    -
+ D    E     MTRR -> PAT disable         Disabled   BIOS
+ D    D     MTRR -> PAT disable         Disabled    -
+ -    np/E  PAT  -> PAT disable         Disabled   BIOS
+ -    np/D  PAT  -> PAT disable         Disabled    -
+ E    !P/E  MTRR -> PAT init            Disabled   BIOS
+ D    !P/E  MTRR -> PAT disable         Disabled   BIOS
+ !M   !P/E  MTRR stub -> PAT disable    Disabled   BIOS
+
+ Legend
+ ------------------------------------------------
+ E         Feature enabled in CPU
+ D	   Feature disabled/unsupported in CPU
+ np	   "nopat" boot option specified
+ !P	   CONFIG_X86_PAT option unset
+ !M	   CONFIG_MTRR option unset
+ Enabled   PAT state set to enabled
+ Disabled  PAT state set to disabled
+ OS        PAT initializes PAT MSR with OS setting
+ BIOS      PAT keeps PAT MSR with BIOS setting
+

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Toshi Kani <[email protected]>

commit 1886297ce0c8d563a08c8a8c4c0b97743e06cd37 upstream.

The following BUG_ON() crash was reported on QEMU/i386:

kernel BUG at arch/x86/mm/physaddr.c:79!

  Call Trace:
  phys_mem_access_prot_allowed
  mmap_mem
  ? mmap_region
  mmap_region
  do_mmap
  vm_mmap_pgoff
  SyS_mmap_pgoff
  do_int80_syscall_32
  entry_INT80_32

after commit:

edfe63ec97ed ("x86/mtrr: Fix Xorg crashes in Qemu sessions")

PAT is now set to disabled state when MTRRs are disabled. Thus, reactivating the __pa(high_memory) check in phys_mem_access_prot_allowed().

When CONFIG_DEBUG_VIRTUAL is set, __pa() calls __phys_addr(), which in turn calls slow_virt_to_phys() for 'high_memory'. Because 'high_memory' is set to (the max direct mapped virt addr + 1), it is not a valid virtual address. Hence, slow_virt_to_phys() returns 0 and hit the BUG_ON. Using __pa_nodebug() instead of __pa() will fix this BUG_ON.

However, this code block, originally written for Pentiums and earlier, is no longer adequate since a 32-bit Xen guest has MTRRs disabled and supports ZONE_HIGHMEM. In this setup, this code sets UC attribute for accessing RAM in high memory range.

Delete this code block as it has been unused for a long time.

---
 arch/x86/mm/pat.c |   19 -------------------
 1 file changed, 19 deletions(-)

@@ -777,25 +777,6 @@ int phys_mem_access_prot_allowed(struct
 	if (file->f_flags & O_DSYNC)
 		pcm = _PAGE_CACHE_MODE_UC_MINUS;
 
-#ifdef CONFIG_X86_32
-	/*
-	 * On the PPro and successors, the MTRRs are used to set
-	 * memory types for physical addresses outside main memory,
-	 * so blindly setting UC or PWT on those pages is wrong.
-	 * For Pentiums and earlier, the surround logic should disable
-	 * caching for the high addresses through the KEN pin, but
-	 * we maintain the tradition of paranoia in this code.
-	 */
-	if (!pat_enabled() &&
-	    !(boot_cpu_has(X86_FEATURE_MTRR) ||
-	      boot_cpu_has(X86_FEATURE_K6_MTRR) ||
-	      boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
-	      boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
-	    (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
-		pcm = _PAGE_CACHE_MODE_UC;
-	}
-#endif
-
 	*vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
 			     cachemode2protval(pcm));
 	return 1;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Matt Roper <[email protected]>

commit e2e407dc093f530b771ee8bf8fe1be41e3cea8b3 upstream.

Due to our lack of two-step watermark programming, our driver has historically pretended that the cursor plane is always on for the purpose of watermark calculations; this helps avoid serious flickering when the cursor turns off/on (e.g., when the user moves the mouse pointer to a different screen). That workaround was accidentally dropped as we started working toward atomic watermark updates. Since we still aren't quite there yet with two-stage updates, we need to resurrect the workaround and treat the cursor as always active.

v2: Tweak cursor width calculations slightly to more closely match the
logic we used before the atomic overhaul began. (Ville)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93892

---
 drivers/gpu/drm/i915/intel_pm.c |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

@@ -1789,16 +1789,20 @@ static uint32_t ilk_compute_cur_wm(const
 				   const struct intel_plane_state *pstate,
 				   uint32_t mem_value)
 {
-	int bpp = pstate->base.fb ? pstate->base.fb->bits_per_pixel / 8 : 0;
+	/*
+	 * We treat the cursor plane as always-on for the purposes of watermark
+	 * calculation.  Until we have two-stage watermark programming merged,
+	 * this is necessary to avoid flickering.
+	 */
+	int cpp = 4;
+	int width = pstate->visible ? pstate->base.crtc_w : 64;
 
-	if (!cstate->base.active || !pstate->visible)
+	if (!cstate->base.active)
 		return 0;
 
 	return ilk_wm_method2(ilk_pipe_pixel_rate(cstate),
 			      cstate->base.adjusted_mode.crtc_htotal,
-			      drm_rect_width(&pstate->dst),
-			      bpp,
-			      mem_value);
+			      width, cpp, mem_value);
 }
 
 /* Only for WM_LP. */

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Johannes Weiner <[email protected]>

commit 73f576c04b9410ed19660f74f97521bee6e1c546 upstream.

The memory controller has quite a bit of state that usually outlives the cgroup and pins its CSS until said state disappears. At the same time it imposes a 16-bit limit on the CSS ID space to economically store IDs in the wild. Consequently, when we use cgroups to contain frequent but small and short-lived jobs that leave behind some page cache, we quickly run into the 64k limitations of outstanding CSSs. Creating a new cgroup fails with -ENOSPC while there are only a few, or even no user-visible cgroups in existence.

Although pinning CSSs past cgroup removal is common, there are only two instances that actually need an ID after a cgroup is deleted: cache shadow entries and swapout records.

Cache shadow entries reference the ID weakly and can deal with the CSS having disappeared when it's looked up later. They pose no hurdle.

Swap-out records do need to pin the css to hierarchically attribute swapins after the cgroup has been deleted; though the only pages that remain swapped out after offlining are tmpfs/shmem pages. And those references are under the user's control, so they are manageable.

This patch introduces a private 16-bit memcg ID and switches swap and cache shadow entries over to using that. This ID can then be recycled after offlining when the CSS remains pinned only by objects that don't specifically need it.

This script demonstrates the problem by faulting one cache page in a new cgroup and deleting it again:

  set -e
  mkdir -p pages
  for x in `seq 128000`; do
    [ $((x % 1000)) -eq 0 ] && echo $x
    mkdir /cgroup/foo
    echo $$ >/cgroup/foo/cgroup.procs
    echo trex >pages/$x
    echo $$ >/cgroup/cgroup.procs
    rmdir /cgroup/foo
  done

When run on an unpatched kernel, we eventually run out of possible IDs even though there are no visible cgroups:

[root@ham ~]# ./cssidstress.sh
[...]
65000
mkdir: cannot create directory '/cgroup/foo': No space left on device

After this patch, the IDs get released upon cgroup destruction and the cache and css objects get released once memory reclaim kicks in.

---
 include/linux/memcontrol.h |    8 +++
 mm/memcontrol.c            |   95 ++++++++++++++++++++++++++++++++++++---------
 mm/slab_common.c           |    2 
 3 files changed, 85 insertions(+), 20 deletions(-)

@@ -174,6 +174,11 @@ struct mem_cgroup_thresholds {
 	struct mem_cgroup_threshold_ary *spare;
 };
 
+struct mem_cgroup_id {
+	int id;
+	atomic_t ref;
+};
+
 /*
  * The memory controller data structure. The memory controller controls both
  * page cache and RSS per cgroup. We would eventually like to provide

@@ -183,6 +188,9 @@ struct mem_cgroup_thresholds {
 struct mem_cgroup {
 	struct cgroup_subsys_state css;
 
+	/* Private memcg ID. Used to ID objects that outlive the cgroup */
+	struct mem_cgroup_id id;
+
 	/* Accounted resources */
 	struct page_counter memory;
 	struct page_counter memsw;

@@ -522,7 +522,7 @@ void memcg_create_kmem_cache(struct mem_
 
 	cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf));
 	cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
-			       css->id, memcg_name_buf);
+			       css->serial_nr, memcg_name_buf);
 	if (!cache_name)
 		goto out_unlock;
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vladimir Davydov <[email protected]>

commit 1f47b61fb4077936465dcde872a4e5cc4fe708da upstream.

An offline memory cgroup might have anonymous memory or shmem left charged to it and no swap. Since only swap entries pin the id of an offline cgroup, such a cgroup will have no id and so an attempt to swapout its anon/shmem will not store memory cgroup info in the swap cgroup map. As a result, memcg->swap or memcg->memsw will never get uncharged from it and any of its ascendants.

Fix this by always charging swapout to the first ancestor cgroup that hasn't released its id yet.

---
 mm/memcontrol.c |   37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

@@ -4141,6 +4141,24 @@ static void mem_cgroup_id_get(struct mem
 	atomic_inc(&memcg->id.ref);
 }
 
+static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
+{
+	while (!atomic_inc_not_zero(&memcg->id.ref)) {
+		/*
+		 * The root cgroup cannot be destroyed, so it's refcount must
+		 * always be >= 1.
+		 */
+		if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
+			VM_BUG_ON(1);
+			break;
+		}
+		memcg = parent_mem_cgroup(memcg);
+		if (!memcg)
+			memcg = root_mem_cgroup;
+	}
+	return memcg;
+}
+
 static void mem_cgroup_id_put(struct mem_cgroup *memcg)
 {
 	if (atomic_dec_and_test(&memcg->id.ref)) {

@@ -5723,7 +5741,7 @@ subsys_initcall(mem_cgroup_init);
  */
 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
 {
-	struct mem_cgroup *memcg;
+	struct mem_cgroup *memcg, *swap_memcg;
 	unsigned short oldid;
 
 	VM_BUG_ON_PAGE(PageLRU(page), page);

@@ -5738,16 +5756,27 @@ void mem_cgroup_swapout(struct page *pag
 	if (!memcg)
 		return;
 
-	mem_cgroup_id_get(memcg);
-	oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
+	/*
+	 * In case the memcg owning these pages has been offlined and doesn't
+	 * have an ID allocated to it anymore, charge the closest online
+	 * ancestor for the swap instead and transfer the memory+swap charge.
+	 */
+	swap_memcg = mem_cgroup_id_get_online(memcg);
+	oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg));
 	VM_BUG_ON_PAGE(oldid, page);
-	mem_cgroup_swap_statistics(memcg, true);
+	mem_cgroup_swap_statistics(swap_memcg, true);
 
 	page->mem_cgroup = NULL;
 
 	if (!mem_cgroup_is_root(memcg))
 		page_counter_uncharge(&memcg->memory, 1);
 
+	if (memcg != swap_memcg) {
+		if (!mem_cgroup_is_root(swap_memcg))
+			page_counter_charge(&swap_memcg->memsw, 1);
+		page_counter_uncharge(&memcg->memsw, 1);
+	}
+
 	/*
 	 * Interrupts should be disabled here because the caller holds the
 	 * mapping->tree_lock lock which is taken with interrupts-off. It is

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vladimir Davydov <[email protected]>

commit 615d66c37c755c49ce022c9e5ac0875d27d2603d upstream.

Since commit 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after many small jobs") swap entries do not pin memcg->css.refcnt directly. Instead, they pin memcg->id.ref. So we should adjust the reference counters accordingly when moving swap charges between cgroups.

---
 mm/memcontrol.c |   24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

@@ -4136,9 +4136,9 @@ static struct cftype mem_cgroup_legacy_f
 
 static DEFINE_IDR(mem_cgroup_idr);
 
-static void mem_cgroup_id_get(struct mem_cgroup *memcg)
+static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
 {
-	atomic_inc(&memcg->id.ref);
+	atomic_add(n, &memcg->id.ref);
 }
 
 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)

@@ -4159,9 +4159,9 @@ static struct mem_cgroup *mem_cgroup_id_
 	return memcg;
 }
 
-static void mem_cgroup_id_put(struct mem_cgroup *memcg)
+static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
 {
-	if (atomic_dec_and_test(&memcg->id.ref)) {
+	if (atomic_sub_and_test(n, &memcg->id.ref)) {
 		idr_remove(&mem_cgroup_idr, memcg->id.id);
 		memcg->id.id = 0;
 

@@ -4170,6 +4170,16 @@ static void mem_cgroup_id_put(struct mem
 	}
 }
 
+static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
+{
+	mem_cgroup_id_get_many(memcg, 1);
+}
+
+static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
+{
+	mem_cgroup_id_put_many(memcg, 1);
+}
+
 /**
  * mem_cgroup_from_id - look up a memcg from a memcg id
  * @id: the memcg id to look up

@@ -4856,6 +4866,8 @@ static void __mem_cgroup_clear_mc(void)
 		if (!mem_cgroup_is_root(mc.from))
 			page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
 
+		mem_cgroup_id_put_many(mc.from, mc.moved_swap);
+
 		/*
 		 * we charged both to->memory and to->memsw, so we
 		 * should uncharge to->memory.

@@ -4863,9 +4875,9 @@ static void __mem_cgroup_clear_mc(void)
 		if (!mem_cgroup_is_root(mc.to))
 			page_counter_uncharge(&mc.to->memory, mc.moved_swap);
 
-		css_put_many(&mc.from->css, mc.moved_swap);
+		mem_cgroup_id_get_many(mc.to, mc.moved_swap);
+		css_put_many(&mc.to->css, mc.moved_swap);
 
-		/* we've already done css_get(mc.to) */
 		mc.moved_swap = 0;
 	}
 	memcg_oom_recover(from);

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: David Howells <[email protected]>

commit f7d665627e103e82d34306c7d3f6f46f387c0d8b upstream.

x86_64 needs to use compat_sys_keyctl for 32-bit userspace rather than calling sys_keyctl(). The latter will work in a lot of cases, thereby hiding the issue.

---
 arch/x86/entry/syscalls/syscall_32.tbl |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -294,7 +294,7 @@
 # 285 sys_setaltroot
 286	i386	add_key			sys_add_key
 287	i386	request_key		sys_request_key
-288	i386	keyctl			sys_keyctl
+288	i386	keyctl			sys_keyctl			compat_sys_keyctl
 289	i386	ioprio_set		sys_ioprio_set
 290	i386	ioprio_get		sys_ioprio_get
 291	i386	inotify_init		sys_inotify_init

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vegard Nossum <[email protected]>

commit 77da160530dd1dc94f6ae15a981f24e5f0021e84 upstream.

I got a KASAN report of use-after-free:

    ==================================================================
    BUG: KASAN: use-after-free in klist_iter_exit+0x61/0x70 at addr ffff8800b6581508
    Read of size 8 by task trinity-c1/315
    =============================================================================
    BUG kmalloc-32 (Not tainted): kasan: bad access detected
    -----------------------------------------------------------------------------

    Disabling lock debugging due to kernel taint
    INFO: Allocated in disk_seqf_start+0x66/0x110 age=144 cpu=1 pid=315
            ___slab_alloc+0x4f1/0x520
            __slab_alloc.isra.58+0x56/0x80
            kmem_cache_alloc_trace+0x260/0x2a0
            disk_seqf_start+0x66/0x110
            traverse+0x176/0x860
            seq_read+0x7e3/0x11a0
            proc_reg_read+0xbc/0x180
            do_loop_readv_writev+0x134/0x210
            do_readv_writev+0x565/0x660
            vfs_readv+0x67/0xa0
            do_preadv+0x126/0x170
            SyS_preadv+0xc/0x10
            do_syscall_64+0x1a1/0x460
            return_from_SYSCALL_64+0x0/0x6a
    INFO: Freed in disk_seqf_stop+0x42/0x50 age=160 cpu=1 pid=315
            __slab_free+0x17a/0x2c0
            kfree+0x20a/0x220
            disk_seqf_stop+0x42/0x50
            traverse+0x3b5/0x860
            seq_read+0x7e3/0x11a0
            proc_reg_read+0xbc/0x180
            do_loop_readv_writev+0x134/0x210
            do_readv_writev+0x565/0x660
            vfs_readv+0x67/0xa0
            do_preadv+0x126/0x170
            SyS_preadv+0xc/0x10
            do_syscall_64+0x1a1/0x460
            return_from_SYSCALL_64+0x0/0x6a

    CPU: 1 PID: 315 Comm: trinity-c1 Tainted: G    B           4.7.0+ #62
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
     ffffea0002d96000 ffff880119b9f918 ffffffff81d6ce81 ffff88011a804480
     ffff8800b6581500 ffff880119b9f948 ffffffff8146c7bd ffff88011a804480
     ffffea0002d96000 ffff8800b6581500 fffffffffffffff4 ffff880119b9f970
    Call Trace:
     [<ffffffff81d6ce81>] dump_stack+0x65/0x84
     [<ffffffff8146c7bd>] print_trailer+0x10d/0x1a0
     [<ffffffff814704ff>] object_err+0x2f/0x40
     [<ffffffff814754d1>] kasan_report_error+0x221/0x520
     [<ffffffff8147590e>] __asan_report_load8_noabort+0x3e/0x40
     [<ffffffff83888161>] klist_iter_exit+0x61/0x70
     [<ffffffff82404389>] class_dev_iter_exit+0x9/0x10
     [<ffffffff81d2e8ea>] disk_seqf_stop+0x3a/0x50
     [<ffffffff8151f812>] seq_read+0x4b2/0x11a0
     [<ffffffff815f8fdc>] proc_reg_read+0xbc/0x180
     [<ffffffff814b24e4>] do_loop_readv_writev+0x134/0x210
     [<ffffffff814b4c45>] do_readv_writev+0x565/0x660
     [<ffffffff814b8a17>] vfs_readv+0x67/0xa0
     [<ffffffff814b8de6>] do_preadv+0x126/0x170
     [<ffffffff814b92ec>] SyS_preadv+0xc/0x10

This problem can occur in the following situation:

open()
- pread()
- .seq_start()
- iter = kmalloc() // succeeds
- seqf->private = iter
- .seq_stop()
- kfree(seqf->private)
- pread()
- .seq_start()
- iter = kmalloc() // fails
- .seq_stop()
- class_dev_iter_exit(seqf->private) // boom! old pointer

As the comment in disk_seqf_stop() says, stop is called even if start failed, so we need to reinitialise the private pointer to NULL when seq iteration stops.

An alternative would be to set the private pointer to NULL when the kmalloc() in disk_seqf_start() fails.

---
 block/genhd.c |    1 +
 1 file changed, 1 insertion(+)

@@ -831,6 +831,7 @@ static void disk_seqf_stop(struct seq_fi
 	if (iter) {
 		class_dev_iter_exit(iter);
 		kfree(iter);
+		seqf->private = NULL;
 	}
 }
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Fabian Frederick <[email protected]>

commit 9b24fef9f0410fb5364245d6cc2bd044cc064007 upstream.

Commit 53dad6d3a8e5 ("ipc: fix race with LSMs") updated ipc_rcu_putref() to receive rcu freeing function but used generic ipc_rcu_free() instead of msg_rcu_free() which does security cleaning.

Running LTP msgsnd06 with kmemleak gives the following:

cat /sys/kernel/debug/kmemleak

unreferenced object 0xffff88003c0a11f8 (size 8):

    comm "msgsnd06", pid 1645, jiffies 4294672526 (age 6.549s)
    hex dump (first 8 bytes):
      1b 00 00 00 01 00 00 00                          ........
    backtrace:
      kmemleak_alloc+0x23/0x40
      kmem_cache_alloc_trace+0xe1/0x180
      selinux_msg_queue_alloc_security+0x3f/0xd0
      security_msg_queue_alloc+0x2e/0x40
      newque+0x4e/0x150
      ipcget+0x159/0x1b0
      SyS_msgget+0x39/0x40
      entry_SYSCALL_64_fastpath+0x13/0x8f

Manfred Spraul suggested to fix sem.c as well and Davidlohr Bueso to only use ipc_rcu_free in case of security allocation failure in newary()

---
 ipc/msg.c |    2 +-
 ipc/sem.c |   12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

@@ -680,7 +680,7 @@ long do_msgsnd(int msqid, long mtype, vo
 		rcu_read_lock();
 		ipc_lock_object(&msq->q_perm);
 
-		ipc_rcu_putref(msq, ipc_rcu_free);
+		ipc_rcu_putref(msq, msg_rcu_free);
 		/* raced with RMID? */
 		if (!ipc_valid_object(&msq->q_perm)) {
 			err = -EIDRM;

@@ -442,7 +442,7 @@ static inline struct sem_array *sem_obta
 static inline void sem_lock_and_putref(struct sem_array *sma)
 {
 	sem_lock(sma, NULL, -1);
-	ipc_rcu_putref(sma, ipc_rcu_free);
+	ipc_rcu_putref(sma, sem_rcu_free);
 }
 
 static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)

@@ -1385,7 +1385,7 @@ static int semctl_main(struct ipc_namesp
 			rcu_read_unlock();
 			sem_io = ipc_alloc(sizeof(ushort)*nsems);
 			if (sem_io == NULL) {
-				ipc_rcu_putref(sma, ipc_rcu_free);
+				ipc_rcu_putref(sma, sem_rcu_free);
 				return -ENOMEM;
 			}
 

@@ -1419,20 +1419,20 @@ static int semctl_main(struct ipc_namesp
 		if (nsems > SEMMSL_FAST) {
 			sem_io = ipc_alloc(sizeof(ushort)*nsems);
 			if (sem_io == NULL) {
-				ipc_rcu_putref(sma, ipc_rcu_free);
+				ipc_rcu_putref(sma, sem_rcu_free);
 				return -ENOMEM;
 			}
 		}
 
 		if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) {
-			ipc_rcu_putref(sma, ipc_rcu_free);
+			ipc_rcu_putref(sma, sem_rcu_free);
 			err = -EFAULT;
 			goto out_free;
 		}
 
 		for (i = 0; i < nsems; i++) {
 			if (sem_io[i] > SEMVMX) {
-				ipc_rcu_putref(sma, ipc_rcu_free);
+				ipc_rcu_putref(sma, sem_rcu_free);
 				err = -ERANGE;
 				goto out_free;
 			}

@@ -1722,7 +1722,7 @@ static struct sem_undo *find_alloc_undo(
 	/* step 2: allocate new undo structure */
 	new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
 	if (!new) {
-		ipc_rcu_putref(sma, ipc_rcu_free);
+		ipc_rcu_putref(sma, sem_rcu_free);
 		return ERR_PTR(-ENOMEM);
 	}
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alexey Kuznetsov <[email protected]>

commit ac7f052b9e1534c8248f814b6f0068ad8d4a06d2 upstream.

Due to implementation of fuse writeback filemap_write_and_wait_range() does not catch errors. We have to do this directly after fuse_sync_writes()

---
 fs/fuse/file.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

@@ -462,6 +462,21 @@ int fuse_fsync_common(struct file *file,
 		goto out;
 
 	fuse_sync_writes(inode);
+
+	/*
+	 * Due to implementation of fuse writeback
+	 * filemap_write_and_wait_range() does not catch errors.
+	 * We have to do this directly after fuse_sync_writes()
+	 */
+	if (test_bit(AS_ENOSPC, &file->f_mapping->flags) &&
+	    test_and_clear_bit(AS_ENOSPC, &file->f_mapping->flags))
+		err = -ENOSPC;
+	if (test_bit(AS_EIO, &file->f_mapping->flags) &&
+	    test_and_clear_bit(AS_EIO, &file->f_mapping->flags))
+		err = -EIO;
+	if (err)
+		goto out;
+
 	err = sync_inode_metadata(inode, 1);
 	if (err)
 		goto out;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Maxim Patlasov <[email protected]>

commit 9ebce595f63a407c5cec98f98f9da8459b73740a upstream.

fuse_flush() calls write_inode_now() that triggers writeback, but actual writeback will happen later, on fuse_sync_writes(). If an error happens, fuse_writepage_end() will set error bit in mapping->flags. So, we have to check mapping->flags after fuse_sync_writes().

---
 fs/fuse/file.c |    9 +++++++++
 1 file changed, 9 insertions(+)

@@ -417,6 +417,15 @@ static int fuse_flush(struct file *file,
 	fuse_sync_writes(inode);
 	mutex_unlock(&inode->i_mutex);
 
+	if (test_bit(AS_ENOSPC, &file->f_mapping->flags) &&
+	    test_and_clear_bit(AS_ENOSPC, &file->f_mapping->flags))
+		err = -ENOSPC;
+	if (test_bit(AS_EIO, &file->f_mapping->flags) &&
+	    test_and_clear_bit(AS_EIO, &file->f_mapping->flags))
+		err = -EIO;
+	if (err)
+		return err;
+
 	req = fuse_get_req_nofail_nopages(fc, file);
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.fh = ff->fh;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Wei Fang <[email protected]>

commit 9446385f05c9af25fed53dbed3cc75763730be52 upstream.

FUSE_HAS_IOCTL_DIR should be assigned to ->flags, it may be a typo.

---
 fs/fuse/inode.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -926,7 +926,7 @@ static void fuse_send_init(struct fuse_c
 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
-		FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
+		FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
 		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
 		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT;
 	req->in.h.opcode = FUSE_INIT;

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Wei Fang <[email protected]>

commit 47be61845c775643f1aa4d2a54343549f943c94c upstream.

We triggered soft-lockup under stress test which open/access/write/close one file concurrently on more than five different CPUs:

WARN: soft lockup - CPU#0 stuck for 11s! [who:30631]
...

[<ffffffc0003986f8>] dput+0x100/0x298
[<ffffffc00038c2dc>] terminate_walk+0x4c/0x60
[<ffffffc00038f56c>] path_lookupat+0x5cc/0x7a8
[<ffffffc00038f780>] filename_lookup+0x38/0xf0
[<ffffffc000391180>] user_path_at_empty+0x78/0xd0
[<ffffffc0003911f4>] user_path_at+0x1c/0x28
[<ffffffc00037d4fc>] SyS_faccessat+0xb4/0x230

->d_lock trylock may failed many times because of concurrently operations, and dput() may execute a long time.

Fix this by replacing cpu_relax() with cond_resched(). dput() used to be sleepable, so make it sleepable again should be safe.

---
 fs/dcache.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

@@ -578,7 +578,6 @@ static struct dentry *dentry_kill(struct
 
 failed:
 	spin_unlock(&dentry->d_lock);
-	cpu_relax();
 	return dentry; /* try again with same dentry */
 }
 

@@ -752,6 +751,8 @@ void dput(struct dentry *dentry)
 		return;
 
 repeat:
+	might_sleep();
+
 	rcu_read_lock();
 	if (likely(fast_dput(dentry))) {
 		rcu_read_unlock();

@@ -783,8 +784,10 @@ repeat:
 
 kill_it:
 	dentry = dentry_kill(dentry);
-	if (dentry)
+	if (dentry) {
+		cond_resched();
 		goto repeat;
+	}
 }
 EXPORT_SYMBOL(dput);
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Herbert Xu <[email protected]>

commit b30bdfa86431afbafe15284a3ad5ac19b49b88e3 upstream.

As it is if you ask for a sync gcm you may actually end up with an async one because it does not filter out async implementations of ghash.

This patch fixes this by adding the necessary filter when looking for ghash.

---
 crypto/gcm.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -639,7 +639,9 @@ static int crypto_gcm_create_common(stru
 
 	ghash_alg = crypto_find_alg(ghash_name, &crypto_ahash_type,
 				    CRYPTO_ALG_TYPE_HASH,
-				    CRYPTO_ALG_TYPE_AHASH_MASK);
+				    CRYPTO_ALG_TYPE_AHASH_MASK |
+				    crypto_requires_sync(algt->type,
+							 algt->mask));
 	if (IS_ERR(ghash_alg))
 		return PTR_ERR(ghash_alg);
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Herbert Xu <[email protected]>

commit 5f070e81bee35f1b7bd1477bb223a873ff657803 upstream.

When there is more data to be processed, the current test in scatterwalk_done may prevent us from calling pagedone even when we should.

In particular, if we're on an SG entry spanning multiple pages where the last page is not a full page, we will incorrectly skip calling pagedone on the second last page.

This patch fixes this by adding a separate test for whether we've reached the end of a page.

---
 crypto/scatterwalk.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -72,7 +72,8 @@ static void scatterwalk_pagedone(struct
 
 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
 {
-	if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more)
+	if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
+	    !(walk->offset & (PAGE_SIZE - 1)))
 		scatterwalk_pagedone(walk, out, more);
 }
 EXPORT_SYMBOL_GPL(scatterwalk_done);

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vegard Nossum <[email protected]>

commit f70749ca42943faa4d4dcce46dfdcaadb1d0c4b6 upstream.

An extent with lblock = 4294967295 and len = 1 will pass the ext4_valid_extent() test:

	ext4_lblk_t last = lblock + len - 1;

	if (len == 0 || lblock > last)
		return 0;

since last = 4294967295 + 1 - 1 = 4294967295. This would later trigger the BUG_ON(es->es_lblk + es->es_len < es->es_lblk) in ext4_es_end().

We can simplify it by removing the - 1 altogether and changing the test to use lblock + len <= lblock, since now if len = 0, then lblock + 0 == lblock and it fails, and if len > 0 then lblock + len > lblock in order to pass (i.e. it doesn't overflow).

---
 fs/ext4/extents.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

@@ -376,9 +376,13 @@ static int ext4_valid_extent(struct inod
 	ext4_fsblk_t block = ext4_ext_pblock(ext);
 	int len = ext4_ext_get_actual_len(ext);
 	ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
-	ext4_lblk_t last = lblock + len - 1;
 
-	if (len == 0 || lblock > last)
+	/*
+	 * We allow neither:
+	 *  - zero length
+	 *  - overflow/wrap-around
+	 */
+	if (lblock + len <= lblock)
 		return 0;
 	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 }

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jan Kara <[email protected]>

commit 646caa9c8e196880b41cd3e3d33a2ebc752bdb85 upstream.

Commit 06bd3c36a733 (ext4: fix data exposure after a crash) uncovered a deadlock in ext4_writepages() which was previously much harder to hit. After this commit xfstest generic/130 reproduces the deadlock on small filesystems.

The problem happens when ext4_do_update_inode() sets LARGE_FILE feature and marks current inode handle as synchronous. That subsequently results in ext4_journal_stop() called from ext4_writepages() to block waiting for transaction commit while still holding page locks, reference to io_end, and some prepared bio in mpd structure each of which can possibly block transaction commit from completing and thus results in deadlock.

Fix the problem by releasing page locks, io_end reference, and submitting prepared bio before calling ext4_journal_stop().

[ Changed to defer the call to ext4_journal_stop() only if the handle
is synchronous. --tytso ]

---
 fs/ext4/inode.c |   29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

@@ -2589,13 +2589,36 @@ retry:
 				done = true;
 			}
 		}
-		ext4_journal_stop(handle);
+		/*
+		 * Caution: If the handle is synchronous,
+		 * ext4_journal_stop() can wait for transaction commit
+		 * to finish which may depend on writeback of pages to
+		 * complete or on page lock to be released.  In that
+		 * case, we have to wait until after after we have
+		 * submitted all the IO, released page locks we hold,
+		 * and dropped io_end reference (for extent conversion
+		 * to be able to complete) before stopping the handle.
+		 */
+		if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
+			ext4_journal_stop(handle);
+			handle = NULL;
+		}
 		/* Submit prepared bio */
 		ext4_io_submit(&mpd.io_submit);
 		/* Unlock pages we didn't use */
 		mpage_release_unused_pages(&mpd, give_up_on_write);
-		/* Drop our io_end reference we got from init */
-		ext4_put_io_end(mpd.io_submit.io_end);
+		/*
+		 * Drop our io_end reference we got from init. We have
+		 * to be careful and use deferred io_end finishing if
+		 * we are still holding the transaction as we can
+		 * release the last reference to io_end which may end
+		 * up doing unwritten extent conversion.
+		 */
+		if (handle) {
+			ext4_put_io_end_defer(mpd.io_submit.io_end);
+			ext4_journal_stop(handle);
+		} else
+			ext4_put_io_end(mpd.io_submit.io_end);
 
 		if (ret == -ENOSPC && sbi->s_journal) {
 			/*

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vegard Nossum <[email protected]>

commit 6a7fd522a7c94cdef0a3b08acf8e6702056e635c upstream.

If ext4_fill_super() fails early, it's possible for ext4_evict_inode() to call ext4_should_journal_data() before superblock options and flags are fully set up. In that case, the iput() on the journal inode can end up causing a BUG().

Work around this problem by reordering the tests so we only call ext4_should_journal_data() after we know it's not the journal inode.

---
 fs/ext4/inode.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

@@ -205,9 +205,9 @@ void ext4_evict_inode(struct inode *inod
 		 * Note that directories do not have this problem because they
 		 * don't use page cache.
 		 */
-		if (ext4_should_journal_data(inode) &&
-		    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
-		    inode->i_ino != EXT4_JOURNAL_INO) {
+		if (inode->i_ino != EXT4_JOURNAL_INO &&
+		    ext4_should_journal_data(inode) &&
+		    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
 			journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
 			tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
 

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Theodore Ts'o <[email protected]>

commit 5b9554dc5bf008ae7f68a52e3d7e76c0920938a2 upstream.

If s_reserved_gdt_blocks is extremely large, it's possible for ext4_init_block_bitmap(), which is called when ext4 sets up an uninitialized block bitmap, to corrupt random kernel memory. Add the same checks which e2fsck has --- it must never be larger than blocksize / sizeof(__u32) --- and then add a backup check in ext4_init_block_bitmap() in case the superblock gets modified after the file system is mounted.