4.19.227-rc1 review

This is the start of the stable review cycle for the 4.19.227 release. There are 3 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 Sat, 29 Jan 2022 18:02:51 +0000. Anything received after that time might be too late.

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

	https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.19.227-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-4.19.y
and the diffstat can be found below.

thanks,

greg k-h

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

Greg Kroah-Hartman <[email protected]>

    Linux 4.19.227-rc1

Jan Kara <[email protected]>
select: Fix indefinitely sleeping task in poll_schedule_timeout()

Nikolay Aleksandrov <[email protected]>
net: bridge: clear bridge's private skb space on xmit

Tvrtko Ursulin <[email protected]>
drm/i915: Flush TLBs before releasing backing store

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

Diffstat:

 Makefile                               |  4 +-
 drivers/gpu/drm/i915/i915_drv.h        |  2 +
 drivers/gpu/drm/i915/i915_gem.c        | 83 ++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_gem_object.h |  1 +
 drivers/gpu/drm/i915/i915_reg.h        |  6 +++
 drivers/gpu/drm/i915/i915_vma.c        |  4 ++
 fs/select.c                            | 63 ++++++++++++++------------
 net/bridge/br_device.c                 |  2 +
 8 files changed, 133 insertions(+), 32 deletions(-)

From: Tvrtko Ursulin <[email protected]>

commit 7938d61591d33394a21bdd7797a245b65428f44c upstream.

We need to flush TLBs before releasing backing store otherwise userspace is able to encounter stale entries if a) it is not declaring access to certain buffers and b) it races with the backing store release from a such undeclared execution already executing on the GPU in parallel.

The approach taken is to mark any buffer objects which were ever bound to the GPU and to trigger a serialized TLB flush when their backing store is released.

Alternatively the flushing could be done on VMA unbind, at which point we would be able to ascertain whether there is potential a parallel GPU execution (which could race), but essentially it boils down to paying the cost of TLB flushes potentially needlessly at VMA unbind time (when the backing store is not known to be going away so not needed for safety), versus potentially needlessly at backing store relase time (since we at that point cannot tell whether there is anything executing on the GPU which uses that object).

Thereforce simplicity of implementation has been chosen for now with scope to benchmark and refine later as required.

---
 drivers/gpu/drm/i915/i915_drv.h        |    2 
 drivers/gpu/drm/i915/i915_gem.c        |   83 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_gem_object.h |    1 
 drivers/gpu/drm/i915/i915_reg.h        |    6 ++
 drivers/gpu/drm/i915/i915_vma.c        |    4 +
 5 files changed, 96 insertions(+)

@@ -1595,6 +1595,8 @@ struct drm_i915_private {
 
 	struct intel_uncore uncore;
 
+	struct mutex tlb_invalidate_lock;
+
 	struct i915_virtual_gpu vgpu;
 
 	struct intel_gvt *gvt;

@@ -136,6 +136,7 @@ struct drm_i915_gem_object {
 	 * activity?
 	 */
 #define I915_BO_ACTIVE_REF 0
+#define I915_BO_WAS_BOUND_BIT    1
 
 	/*
 	 * Is the object to be mapped as read-only to the GPU

@@ -2431,6 +2431,12 @@ enum i915_power_well_id {
 #define   GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING	(1 << 28)
 #define   GAMT_CHKN_DISABLE_I2M_CYCLE_ON_WR_PORT	(1 << 24)
 
+#define GEN8_RTCR	_MMIO(0x4260)
+#define GEN8_M1TCR	_MMIO(0x4264)
+#define GEN8_M2TCR	_MMIO(0x4268)
+#define GEN8_BTCR	_MMIO(0x426c)
+#define GEN8_VTCR	_MMIO(0x4270)
+
 #if 0
 #define PRB0_TAIL	_MMIO(0x2030)
 #define PRB0_HEAD	_MMIO(0x2034)

@@ -335,6 +335,10 @@ int i915_vma_bind(struct i915_vma *vma,
 		return ret;
 
 	vma->flags |= bind_flags;
+
+	if (vma->obj)
+		set_bit(I915_BO_WAS_BOUND_BIT, &vma->obj->flags);
+
 	return 0;
 }
 

From: Nikolay Aleksandrov <[email protected]>

commit fd65e5a95d08389444e8591a20538b3edece0e15 upstream.

We need to clear all of the bridge private skb variables as they can be stale due to the packet being recirculated through the stack and then transmitted through the bridge device. Similar memset is already done on bridge's input. We've seen cases where proxyarp_replied was 1 on routed multicast packets transmitted through the bridge to ports with neigh suppress which were getting dropped. Same thing can in theory happen with the port isolation bit as well.

---
 net/bridge/br_device.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -42,6 +42,8 @@ netdev_tx_t br_dev_xmit(struct sk_buff *
 	struct ethhdr *eth;
 	u16 vid = 0;
 
+	memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
+
 	rcu_read_lock();
 	nf_ops = rcu_dereference(nf_br_ops);
 	if (nf_ops && nf_ops->br_dev_xmit_hook(skb)) {

From: Jan Kara <[email protected]>

commit 68514dacf2715d11b91ca50d88de047c086fea9c upstream.

A task can end up indefinitely sleeping in do_select() -> poll_schedule_timeout() when the following race happens:

TASK1 (thread1) TASK2 TASK1 (thread2)
do_select()
setup poll_wqueues table
with 'fd'
write data to 'fd'
pollwake()
table->triggered = 1
closes 'fd' thread1 is
waiting for
poll_schedule_timeout()
- sees table->triggered
table->triggered = 0
return -EINTR
loop back in do_select()

But at this point when TASK1 loops back, the fdget() in the setup of poll_wqueues fails. So now so we never find 'fd' is ready for reading and sleep in poll_schedule_timeout() indefinitely.

Treat an fd that got closed as a fd on which some event happened. This makes sure cannot block indefinitely in do_select().

Another option would be to return -EBADF in this case but that has a potential of subtly breaking applications that excercise this behavior and it happens to work for them. So returning fd as active seems like a safer choice.

---
 fs/select.c |   63 +++++++++++++++++++++++++++++++-----------------------------
 1 file changed, 33 insertions(+), 30 deletions(-)

@@ -431,9 +431,11 @@ get_max:
 	return max;
 }
 
-#define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR)
-#define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR)
-#define POLLEX_SET (EPOLLPRI)
+#define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR |\
+			EPOLLNVAL)
+#define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR |\
+			 EPOLLNVAL)
+#define POLLEX_SET (EPOLLPRI | EPOLLNVAL)
 
 static inline void wait_key_set(poll_table *wait, unsigned long in,
 				unsigned long out, unsigned long bit,

@@ -500,6 +502,7 @@ static int do_select(int n, fd_set_bits
 					break;
 				if (!(bit & all_bits))
 					continue;
+				mask = EPOLLNVAL;
 				f = fdget(i);
 				if (f.file) {
 					wait_key_set(wait, in, out, bit,

@@ -507,34 +510,34 @@ static int do_select(int n, fd_set_bits
 					mask = vfs_poll(f.file, wait);
 
 					fdput(f);
-					if ((mask & POLLIN_SET) && (in & bit)) {
-						res_in |= bit;
-						retval++;
-						wait->_qproc = NULL;
-					}
-					if ((mask & POLLOUT_SET) && (out & bit)) {
-						res_out |= bit;
-						retval++;
-						wait->_qproc = NULL;
-					}
-					if ((mask & POLLEX_SET) && (ex & bit)) {
-						res_ex |= bit;
-						retval++;
-						wait->_qproc = NULL;
-					}
-					/* got something, stop busy polling */
-					if (retval) {
-						can_busy_loop = false;
-						busy_flag = 0;
-
-					/*
-					 * only remember a returned
-					 * POLL_BUSY_LOOP if we asked for it
-					 */
-					} else if (busy_flag & mask)
-						can_busy_loop = true;
-
 				}
+				if ((mask & POLLIN_SET) && (in & bit)) {
+					res_in |= bit;
+					retval++;
+					wait->_qproc = NULL;
+				}
+				if ((mask & POLLOUT_SET) && (out & bit)) {
+					res_out |= bit;
+					retval++;
+					wait->_qproc = NULL;
+				}
+				if ((mask & POLLEX_SET) && (ex & bit)) {
+					res_ex |= bit;
+					retval++;
+					wait->_qproc = NULL;
+				}
+				/* got something, stop busy polling */
+				if (retval) {
+					can_busy_loop = false;
+					busy_flag = 0;
+
+				/*
+				 * only remember a returned
+				 * POLL_BUSY_LOOP if we asked for it
+				 */
+				} else if (busy_flag & mask)
+					can_busy_loop = true;
+
 			}
 			if (res_in)
 				*rinp = res_in;

Hi!

CIP testing did not find any problems here:

https://gitlab.com/cip-project/cip-testing/linux-stable-rc-ci/-/tree/linux-4.19.y

Best regards,
Pavel

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

Compiled and booted on my test system. No dmesg regressions.

thanks,
-- Shuah

All tests passing for Tegra ...

Test results for stable-v4.19:

    10 builds:	10 pass, 0 fail
    22 boots:	22 pass, 0 fail
    40 tests:	40 pass, 0 fail

Linux version: 4.19.227-rc1-g0f7abe705832
Boards tested: tegra124-jetson-tk1, tegra186-p2771-0000,

                tegra194-p2972-0000, tegra20-ventana,
                tegra210-p2371-2180, tegra30-cardhu-a04

Jon

Hi Greg,

Build test:
mips (gcc version 11.2.1 20220121): 63 configs -> no failure arm (gcc version 11.2.1 20220121): 116 configs -> no new failure arm64 (gcc version 11.2.1 20220121): 2 configs -> no failure x86_64 (gcc version 11.2.1 20220121): 4 configs -> no failure

Boot test:
x86_64: Booted on my test laptop. No regression.
x86_64: Booted on qemu. No regression. [1]

[1]. https://openqa.qa.codethink.co.uk/tests/664

--
Regards
Sudip

Build results:

	total: 155 pass: 155 fail: 0
Qemu test results:
	total: 425 pass: 425 fail: 0

Guenter

Results from Linaro’s test farm.
No regressions on arm64, arm, x86_64, and i386.

## Build
* kernel: 4.19.227-rc1
* git: https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc
* git branch: linux-4.19.y
* git commit: 0f7abe705832c477bd2571c77981ca3034202ace
* git describe: v4.19.226-4-g0f7abe705832
* test details:
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-4.19.y/build/v4.19.226-4-g0f7abe705832

## Test Regressions (compared to v4.19.225-239-gcedebae149c2) No test regressions found.

## Metric Regressions (compared to v4.19.225-239-gcedebae149c2) No metric regressions found.

## Test Fixes (compared to v4.19.225-239-gcedebae149c2) No test fixes found.

## Metric Fixes (compared to v4.19.225-239-gcedebae149c2) No metric fixes found.

## Test result summary
total: 78421, pass: 63758, fail: 737, skip: 12182, xfail: 1744

## Build Summary
* arm: 250 total, 246 passed, 4 failed
* arm64: 35 total, 35 passed, 0 failed
* dragonboard-410c: 1 total, 1 passed, 0 failed
* hi6220-hikey: 1 total, 1 passed, 0 failed
* i386: 19 total, 19 passed, 0 failed
* juno-r2: 1 total, 1 passed, 0 failed
* mips: 26 total, 26 passed, 0 failed
* powerpc: 52 total, 48 passed, 4 failed
* s390: 12 total, 12 passed, 0 failed
* sparc: 12 total, 12 passed, 0 failed
* x15: 1 total, 1 passed, 0 failed
* x86: 1 total, 1 passed, 0 failed
* x86_64: 34 total, 34 passed, 0 failed

## Test suites summary
* fwts
* kselftest-android
* kselftest-arm64
* kselftest-arm64/arm64.btitest.bti_c_func
* kselftest-arm64/arm64.btitest.bti_j_func
* kselftest-arm64/arm64.btitest.bti_jc_func
* kselftest-arm64/arm64.btitest.bti_none_func
* kselftest-arm64/arm64.btitest.nohint_func
* kselftest-arm64/arm64.btitest.paciasp_func
* kselftest-arm64/arm64.nobtitest.bti_c_func
* kselftest-arm64/arm64.nobtitest.bti_j_func
* kselftest-arm64/arm64.nobtitest.bti_jc_func
* kselftest-arm64/arm64.nobtitest.bti_none_func
* kselftest-arm64/arm64.nobtitest.nohint_func
* kselftest-arm64/arm64.nobtitest.paciasp_func
* kselftest-bpf
* kselftest-breakpoints
* kselftest-capabilities
* kselftest-cgroup
* kselftest-clone3
* kselftest-core
* kselftest-cpu-hotplug
* kselftest-cpufreq
* kselftest-drivers
* kselftest-efivarfs
* kselftest-filesystems
* kselftest-firmware
* kselftest-fpu
* kselftest-futex
* kselftest-gpio
* kselftest-intel_pstate
* kselftest-ipc
* kselftest-ir
* kselftest-kcmp
* kselftest-kexec
* kselftest-kvm
* kselftest-lib
* kselftest-livepatch
* kselftest-membarrier
* kselftest-memfd
* kselftest-memory-hotplug
* kselftest-mincore
* kselftest-mount
* kselftest-mqueue
* kselftest-net
* kselftest-netfilter
* kselftest-nsfs
* kselftest-openat2
* kselftest-pid_namespace
* kselftest-pidfd
* kselftest-proc
* kselftest-pstore
* kselftest-ptrace
* kselftest-rseq
* kselftest-rtc
* kselftest-seccomp
* kselftest-sigaltstack
* kselftest-size
* kselftest-splice
* kselftest-static_keys
* kselftest-sync
* kselftest-sysctl
* kselftest-tc-testing
* kselftest-timens
* kselftest-timers
* kselftest-tmpfs
* kselftest-tpm2
* kselftest-user
* kselftest-vm
* kselftest-x86
* kselftest-zram
* kvm-unit-tests
* libhugetlbfs
* linux-log-parser
* ltp-cap_bounds-tests
* ltp-commands-tests
* ltp-containers-tests
* ltp-controllers-tests
* ltp-cpuhotplug-tests
* ltp-crypto-tests
* ltp-cve-tests
* ltp-dio-tests
* ltp-fcntl-locktests-tests
* ltp-filecaps-tests
* ltp-fs-tests
* ltp-fs_bind-tests
* ltp-fs_perms_simple-tests
* ltp-fsx-tests
* ltp-hugetlb-tests
* ltp-io-tests
* ltp-ipc-tests
* ltp-math-tests
* ltp-mm-tests
* ltp-nptl-tests
* ltp-open-posix-tests
* ltp-pty-tests
* ltp-sched-tests
* ltp-securebits-tests
* ltp-syscalls-tests
* ltp-tracing-tests
* network-basic-tests
* packetdrill
* perf
* rcutorture
* ssuite
* v4l2-compliance

--
Linaro LKFT
https://lkft.linaro.org