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BUG: sleeping function called from invalid context at mm/slab.h:LINE (4)

PATCH In review syzbot 3 participants 4 messages Jul 9, 2018 – Dec 23, 2018

Subsystems (2)
x86 Crypto API
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author syzbot
#0 lore raw

Hello,

syzbot found the following crash on:

HEAD commit:    d00d6d9a339d Add linux-next specific files for 20180709
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10ad4968400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=94fe2b586beccacd
dashboard link: https://syzkaller.appspot.com/bug?extid=9bf843c33f782d73ae7d
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:

Reported-by [email protected]

RAX: ffffffffffffffda RBX: cccccccccccccccd RCX: 0000000000410081
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fc453c22850
RBP: 000000000072bea0 R08: 000000000000000f R09: 0000000000000000
R10: 0000000020000100 R11: 0000000000000293 R12: 0000000000000015
R13: 00000000004c289a R14: 00000000004d41c8 R15: 0000000000000004

BUG: sleeping function called from invalid context at mm/slab.h:421
in_atomic(): 1, irqs_disabled(): 0, pid: 24283, name: syz-executor7
INFO: lockdep is turned off.
CPU: 1 PID: 24283 Comm: syz-executor7 Not tainted 4.18.0-rc3-next-20180709+ #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 ___might_sleep.cold.86+0x11f/0x13a kernel/sched/core.c:6187
 __might_sleep+0x95/0x190 kernel/sched/core.c:6140
 slab_pre_alloc_hook mm/slab.h:421 [inline]
 slab_alloc mm/slab.c:3378 [inline]
 kmem_cache_alloc_trace+0x2bc/0x780 mm/slab.c:3618
 kmalloc include/linux/slab.h:513 [inline]
 kzalloc include/linux/slab.h:707 [inline]
 kobject_uevent_env+0x20f/0x1110 lib/kobject_uevent.c:514
 kobject_uevent+0x1f/0x30 lib/kobject_uevent.c:636
 kobject_cleanup lib/kobject.c:630 [inline]
 kobject_release lib/kobject.c:672 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x1fb/0x280 lib/kobject.c:689
 put_device+0x20/0x30 drivers/base/core.c:2002
 delete_partition_rcu_cb+0x147/0x1b0 block/partition-generic.c:254
 __rcu_reclaim kernel/rcu/rcu.h:258 [inline]
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2878 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2845 [inline]
 rcu_process_callbacks+0xe01/0x2810 kernel/rcu/tree.c:2862
 __do_softirq+0x2e8/0xb17 kernel/softirq.c:288
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x1d1/0x200 kernel/softirq.c:408
 exiting_irq arch/x86/include/asm/apic.h:527 [inline]
 smp_apic_timer_interrupt+0x186/0x730 arch/x86/kernel/apic/apic.c:1052
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:867
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:69 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:101
Code: 5d c3 66 90 55 65 48 8b 04 25 40 ee 01 00 65 8b 15 5f 73 85 7e 48 89 e5 81 e2 00 01 1f 00 48 8b 75 08 75 2b 8b 90 98 12 00 00 <83> fa 02 75 20 48 8b 88 a0 12 00 00 8b 80 9c 12 00 00 48 8b 11 48
RSP: 0018:ffff8801ca396bb0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff8801c5c62240 RBX: ffff8801c9db6f10 RCX: ffffffff81ac0f6f
RDX: 0000000000000000 RSI: ffffffff81ac0f7d RDI: 0000000000000007
RBP: ffff8801ca396bb0 R08: ffff8801c5c62240 R09: fffff94000d02f5e
R10: fffff94000d02f5e R11: ffffea0006817af3 R12: ffffea0006817ac0
R13: 00007fc4545e3000 R14: dffffc0000000000 R15: 0000000000000000
 constant_test_bit arch/x86/include/asm/bitops.h:328 [inline]
 PageCompound include/linux/page-flags.h:156 [inline]
 page_mapcount include/linux/mm.h:613 [inline]
 zap_pte_range mm/memory.c:1340 [inline]
 zap_pmd_range mm/memory.c:1443 [inline]
 zap_pud_range mm/memory.c:1472 [inline]
 zap_p4d_range mm/memory.c:1493 [inline]
 unmap_page_range+0xf7d/0x2220 mm/memory.c:1514
 unmap_single_vma+0x1a0/0x310 mm/memory.c:1559
 unmap_vmas+0x120/0x1f0 mm/memory.c:1589
 exit_mmap+0x2c2/0x5b0 mm/mmap.c:3106
 __mmput kernel/fork.c:974 [inline]
 mmput+0x265/0x620 kernel/fork.c:995
 exit_mm kernel/exit.c:544 [inline]
 do_exit+0xea9/0x2750 kernel/exit.c:856
 do_group_exit+0x177/0x440 kernel/exit.c:972
 get_signal+0x88e/0x1970 kernel/signal.c:2467
 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455e29
Code: 38 4c 8b 95 30 fb ff ff 4c 8b 85 20 fb ff ff 49 39 c2 0f 85 b2 f4 ff ff 44 8b 8d 28 fb ff ff b8 ff ff ff 7f 44 29 c8 48 98 49 <39> c2 0f 86 00 f9 ff ff 48 c7 c0 d0 ff ff ff 64 c7 00 4b 00 00 00
RSP: 002b:00007fc453c22ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000072bec0 RCX: 0000000000455e29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072bec0
RBP: 000000000072bec0 R08: 0000000000000035 R09: 000000000072bea0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff0111086f R14: 00007fc453c239c0 R15: 0000000000000000

netlink: 'syz-executor3': attribute type 10 has an invalid length.
netlink: 'syz-executor3': attribute type 10 has an invalid length.

---
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author syzbot
#1 lore raw
syzbot has found a reproducer for the following crash on:

syzbot has found a reproducer for the following crash on:

HEAD commit:    d14b746c6c1c Add linux-next specific files for 20181214
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=129bc943400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1da6d2d18f803140
dashboard link: https://syzkaller.appspot.com/bug?extid=9bf843c33f782d73ae7d
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=136154cd400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1687bfa3400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:

Reported-by [email protected]

sshd (6035) used greatest stack depth: 15600 bytes left

BUG: sleeping function called from invalid context at mm/slab.h:421

in_atomic(): 1, irqs_disabled(): 0, pid: 6051, name: syz-executor515 1 lock held by syz-executor515/6051:
#0: 000000002f6552ef (sk_lock-AF_ALG){+.+.}, at: lock_sock
include/net/sock.h:1502 [inline]
#0: 000000002f6552ef (sk_lock-AF_ALG){+.+.}, at:
skcipher_recvmsg+0xbb/0x1420 crypto/algif_skcipher.c:163 Preemption disabled at:

[<ffffffff812e4ae6>] kernel_fpu_begin+0x16/0x260 arch/x86/kernel/fpu/core.c:127
CPU: 0 PID: 6051 Comm: syz-executor515 Not tainted 4.20.0-rc6-next-20181214+ #171
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 ___might_sleep.cold.86+0x221/0x254 kernel/sched/core.c:6148
 __might_sleep+0x95/0x190 kernel/sched/core.c:6101
 slab_pre_alloc_hook mm/slab.h:421 [inline]
 slab_alloc mm/slab.c:3365 [inline]
 __do_kmalloc mm/slab.c:3707 [inline]
 __kmalloc+0x2da/0x760 mm/slab.c:3718
 kmalloc include/linux/slab.h:550 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 skcipher_next_slow crypto/skcipher.c:254 [inline]
 skcipher_walk_next+0x7f9/0x17f0 crypto/skcipher.c:358
 skcipher_walk_first+0xff/0x3a0 crypto/skcipher.c:441
 skcipher_walk_skcipher+0x541/0x700 crypto/skcipher.c:469
 skcipher_walk_virt+0x58/0xd0 crypto/skcipher.c:479
 chacha_simd_stream_xor+0xb3/0xa40 arch/x86/crypto/chacha_glue.c:141
 chacha_simd+0xd8/0x110 arch/x86/crypto/chacha_glue.c:179
 crypto_skcipher_decrypt include/crypto/skcipher.h:538 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:146 [inline]
 skcipher_recvmsg+0xcc9/0x1420 crypto/algif_skcipher.c:165
 sock_recvmsg_nosec net/socket.c:795 [inline]
 sock_recvmsg+0xd0/0x110 net/socket.c:802
 ___sys_recvmsg+0x2b6/0x680 net/socket.c:2279
 do_recvmmsg+0x303/0xb90 net/socket.c:2392
 __sys_recvmmsg+0x265/0x2a0 net/socket.c:2471
 __do_sys_recvmmsg net/socket.c:2494 [inline]
 __se_sys_recvmmsg net/socket.c:2487 [inline]
 __x64_sys_recvmmsg+0xe6/0x140 net/socket.c:2487
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440349
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff9312c608 EFLAGS: 00000203 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440349
RDX: 0000000000000001 RSI: 000000002000a280 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000203 R12: 00000000
#2 lore raw

PATCH 1/1 crypto: x86/chacha - avoid sleeping under kernel_fpu_begin()

From: Eric Biggers <[email protected]>

Passing atomic=true to skcipher_walk_virt() only makes the later skcipher_walk_done() calls use atomic memory allocations, not skcipher_walk_virt() itself. Thus, we have to move it outside of the preemption-disabled region (kernel_fpu_begin()/kernel_fpu_end()).

(skcipher_walk_virt() only allocates memory for certain layouts of the input scatterlist, hence why I didn't notice this earlier...)

Reported-by [email protected]
Fixes 4af78261870a ("crypto: x86/chacha20 - add XChaCha20 support")
Signed-off-by Eric Biggers <[email protected]>
---
 arch/x86/crypto/chacha_glue.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)
arch/x86/crypto/chacha_glue.c +20 -13
index 9b1d3fac49433..45c1c41431766 100644
@@ -127,30 +127,27 @@ static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
 	}
 }
 
-static int chacha_simd_stream_xor(struct skcipher_request *req,
+static int chacha_simd_stream_xor(struct skcipher_walk *walk,
 				  struct chacha_ctx *ctx, u8 *iv)
 {
 	u32 *state, state_buf[16 + 2] __aligned(8);
-	struct skcipher_walk walk;
 	int next_yield = 4096; /* bytes until next FPU yield */
-	int err;
+	int err = 0;
 
 	BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
 	state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
 
-	err = skcipher_walk_virt(&walk, req, true);
-
 	crypto_chacha_init(state, ctx, iv);
 
-	while (walk.nbytes > 0) {
-		unsigned int nbytes = walk.nbytes;
+	while (walk->nbytes > 0) {
+		unsigned int nbytes = walk->nbytes;
 
-		if (nbytes < walk.total) {
-			nbytes = round_down(nbytes, walk.stride);
+		if (nbytes < walk->total) {
+			nbytes = round_down(nbytes, walk->stride);
 			next_yield -= nbytes;
 		}
 
-		chacha_dosimd(state, walk.dst.virt.addr, walk.src.virt.addr,
+		chacha_dosimd(state, walk->dst.virt.addr, walk->src.virt.addr,
 			      nbytes, ctx->nrounds);
 
 		if (next_yield <= 0) {

@@ -160,7 +157,7 @@ static int chacha_simd_stream_xor(struct skcipher_request *req,
 			next_yield = 4096;
 		}
 
-		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+		err = skcipher_walk_done(walk, walk->nbytes - nbytes);
 	}
 
 	return err;

@@ -170,13 +167,18 @@ static int chacha_simd(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
 	int err;
 
 	if (req->cryptlen <= CHACHA_BLOCK_SIZE || !irq_fpu_usable())
 		return crypto_chacha_crypt(req);
 
+	err = skcipher_walk_virt(&walk, req, true);
+	if (err)
+		return err;
+
 	kernel_fpu_begin();
-	err = chacha_simd_stream_xor(req, ctx, req->iv);
+	err = chacha_simd_stream_xor(&walk, ctx, req->iv);
 	kernel_fpu_end();
 	return err;
 }

@@ -185,6 +187,7 @@ static int xchacha_simd(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
 	struct chacha_ctx subctx;
 	u32 *state, state_buf[16 + 2] __aligned(8);
 	u8 real_iv[16];

@@ -193,6 +196,10 @@ static int xchacha_simd(struct skcipher_request *req)
 	if (req->cryptlen <= CHACHA_BLOCK_SIZE || !irq_fpu_usable())
 		return crypto_xchacha_crypt(req);
 
+	err = skcipher_walk_virt(&walk, req, true);
+	if (err)
+		return err;
+
 	BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
 	state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
 	crypto_chacha_init(state, ctx, req->iv);

@@ -204,7 +211,7 @@ static int xchacha_simd(struct skcipher_request *req)
 
 	memcpy(&real_iv[0], req->iv + 24, 8);
 	memcpy(&real_iv[8], req->iv + 16, 8);
-	err = chacha_simd_stream_xor(req, &subctx, real_iv);
+	err = chacha_simd_stream_xor(&walk, &subctx, real_iv);
 
 	kernel_fpu_end();
Signature · 1 line
2.19.2
maintainer
#3 lore raw

Re: [PATCH] crypto: x86/chacha - avoid sleeping under kernel_fpu_begin()

Quoted 10 lines · Eric Biggers

From: Eric Biggers <[email protected]>

Passing atomic=true to skcipher_walk_virt() only makes the later skcipher_walk_done() calls use atomic memory allocations, not skcipher_walk_virt() itself. Thus, we have to move it outside of the preemption-disabled region (kernel_fpu_begin()/kernel_fpu_end()).

(skcipher_walk_virt() only allocates memory for certain layouts of the input scatterlist, hence why I didn't notice this earlier...)

Quoted 6 lines
Reported-by [email protected]
Fixes 4af78261870a ("crypto: x86/chacha20 - add XChaCha20 support")
Signed-off-by Eric Biggers <[email protected]>
---
 arch/x86/crypto/chacha_glue.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

Patch applied. Thanks.

Signature · 3 lines
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt