possible deadlock in lock

possible deadlock in lock_trace
Status: closed as dup on 2017/12/12 21:59
Reported-by: syzbot+86a008206e8012f85c5feebf2873716e50f33fc4@syzkaller.appspotmail.com
First crash: 1631d, last: 1150d

Duplicate of (1):
Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported
possible deadlock in seq_read	C			19074	1140d	1630d

similar bugs (7):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.19	possible deadlock in lock_trace	syz		error	42	611d	1117d	0/1	upstream: reported syz repro on 2019/04/28 18:16
linux-4.14	possible deadlock in lock_trace	C		error	146	669d	1126d	0/1	upstream: reported C repro on 2019/04/19 09:51
android-49	possible deadlock in lock_trace	C			7424	898d	1134d	0/3	public: reported C repro on 2019/04/12 00:00
upstream	possible deadlock in lock_trace (2)				3	1098d	1128d	0/22	auto-closed as invalid on 2019/10/25 08:41
upstream	possible deadlock in lock_trace (3)	syz	inconclusive	done	69	777d	912d	17/22	fixed on 2020/08/18 22:40
android-414	possible deadlock in lock_trace	syz			203	1142d	1134d	0/1	public: reported syz repro on 2019/04/12 00:01
android-44	possible deadlock in lock_trace	C			41	904d	1134d	0/2	public: reported C repro on 2019/04/11 08:44

Sample crash report:

======================================================
WARNING: possible circular locking dependency detected
4.15.0-rc2-mm1+ #39 Not tainted
------------------------------------------------------
syzkaller408042/3177 is trying to acquire lock:
 (&sig->cred_guard_mutex){+.+.}, at: [<00000000d8b74695>] lock_trace+0x44/0xc0 fs/proc/base.c:407

but task is already holding lock:
 (&p->lock){+.+.}, at: [<00000000453b9d10>] seq_read+0xd5/0x13d0 fs/seq_file.c:165

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&p->lock){+.+.}:
       lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
       seq_read+0xd5/0x13d0 fs/seq_file.c:165
       do_loop_readv_writev fs/read_write.c:673 [inline]
       do_iter_read+0x3db/0x5b0 fs/read_write.c:897
       vfs_readv+0x121/0x1c0 fs/read_write.c:959
       kernel_readv fs/splice.c:361 [inline]
       default_file_splice_read+0x508/0xae0 fs/splice.c:416
       do_splice_to+0x110/0x170 fs/splice.c:880
       do_splice fs/splice.c:1173 [inline]
       SYSC_splice fs/splice.c:1402 [inline]
       SyS_splice+0x11a8/0x1630 fs/splice.c:1382
       entry_SYSCALL_64_fastpath+0x1f/0x96

-> #1 (&pipe->mutex/1){+.+.}:
       lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
       __pipe_lock fs/pipe.c:88 [inline]
       fifo_open+0x15c/0xa40 fs/pipe.c:916
       do_dentry_open+0x682/0xd70 fs/open.c:752
       vfs_open+0x107/0x230 fs/open.c:866
       do_last fs/namei.c:3397 [inline]
       path_openat+0x1157/0x3530 fs/namei.c:3537
       do_filp_open+0x25b/0x3b0 fs/namei.c:3572
       do_open_execat+0x1b9/0x5c0 fs/exec.c:849
       do_execveat_common.isra.30+0x90c/0x22a0 fs/exec.c:1741
       do_execve fs/exec.c:1848 [inline]
       SYSC_execve fs/exec.c:1929 [inline]
       SyS_execve+0x39/0x50 fs/exec.c:1924
       do_syscall_64+0x26c/0x920 arch/x86/entry/common.c:285
       return_from_SYSCALL_64+0x0/0x75

-> #0 (&sig->cred_guard_mutex){+.+.}:
       check_prevs_add kernel/locking/lockdep.c:2031 [inline]
       validate_chain kernel/locking/lockdep.c:2473 [inline]
       __lock_acquire+0x3498/0x47f0 kernel/locking/lockdep.c:3500
       lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
       mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:923
       lock_trace+0x44/0xc0 fs/proc/base.c:407
       proc_pid_syscall+0xa3/0x550 fs/proc/base.c:624
       proc_single_show+0xf8/0x170 fs/proc/base.c:746
       seq_read+0x385/0x13d0 fs/seq_file.c:234
       do_loop_readv_writev fs/read_write.c:673 [inline]
       do_iter_read+0x3db/0x5b0 fs/read_write.c:897
       vfs_readv+0x121/0x1c0 fs/read_write.c:959
       kernel_readv fs/splice.c:361 [inline]
       default_file_splice_read+0x508/0xae0 fs/splice.c:416
       do_splice_to+0x110/0x170 fs/splice.c:880
       do_splice fs/splice.c:1173 [inline]
       SYSC_splice fs/splice.c:1402 [inline]
       SyS_splice+0x11a8/0x1630 fs/splice.c:1382
       entry_SYSCALL_64_fastpath+0x1f/0x96

other info that might help us debug this:

Chain exists of:
  &sig->cred_guard_mutex --> &pipe->mutex/1 --> &p->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&p->lock);
                               lock(&pipe->mutex/1);
                               lock(&p->lock);
  lock(&sig->cred_guard_mutex);

 *** DEADLOCK ***

2 locks held by syzkaller408042/3177:
 #0:  (&pipe->mutex/1){+.+.}, at: [<00000000989db40a>] pipe_lock_nested fs/pipe.c:67 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<00000000989db40a>] pipe_lock+0x56/0x70 fs/pipe.c:75
 #1:  (&p->lock){+.+.}, at: [<00000000453b9d10>] seq_read+0xd5/0x13d0 fs/seq_file.c:165

stack backtrace:
CPU: 1 PID: 3177 Comm: syzkaller408042 Not tainted 4.15.0-rc2-mm1+ #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_circular_bug+0x42d/0x610 kernel/locking/lockdep.c:1271
 check_prev_add+0x666/0x15f0 kernel/locking/lockdep.c:1914
 check_prevs_add kernel/locking/lockdep.c:2031 [inline]
 validate_chain kernel/locking/lockdep.c:2473 [inline]
 __lock_acquire+0x3498/0x47f0 kernel/locking/lockdep.c:3500
 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
 __mutex_lock_common kernel/locking/mutex.c:756 [inline]
 __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
 mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:923
 lock_trace+0x44/0xc0 fs/proc/base.c:407
 proc_pid_syscall+0xa3/0x550 fs/proc/base.c:624
 proc_single_show+0xf8/0x170 fs/proc/base.c:746
 seq_read+0x385/0x13d0 fs/seq_file.c:234
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x3db/0x5b0 fs/read_write.c:897
 vfs_readv+0x121/0x1c0 fs/read_write.c:959
 kernel_readv fs/splice.c:361 [inline]
 default_file_splice_read+0x508/0xae0 fs/splice.c:416
 do_splice_to+0x110/0x170 fs/splice.c:880
 do_splice fs/splice.c:1173 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0x11a8/0x1630 fs/splice.c:1382
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x44a559
RSP: 002b:00007fc37ca0bd28 EFLAGS: 00000212 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007fc37ca0c700 RCX: 000000000044a559
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007ffdb54a6600 R08: 000000000000a3ea R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 00007ffdb54a65ff R14: 00007fc37ca0c9c0 R15: 0000000000000000

Crashes (1847):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-mmots-kasan-gce	2017/12/09 20:46	mmots	82bcf1def3b5	5ad0ce95	.config	log	report	syz	C
ci-upstream-next-kasan-gce	2017/12/03 22:25	linux-next	fb20eb9d798d	16668351	.config	log	report	syz	C
ci-upstream-kasan-gce-root	2018/10/15 22:56	upstream	f0a7d1883d9f	8cd30605	.config	log	report	syz
ci-upstream-kasan-gce	2018/10/15 22:55	upstream	f0a7d1883d9f	8cd30605	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2018/10/15 22:15	upstream	f0a7d1883d9f	8cd30605	.config	log	report	syz
ci-upstream-kasan-gce-selinux-root	2018/10/15 21:20	upstream	f0a7d1883d9f	8cd30605	.config	log	report	syz
ci-upstream-kasan-gce	2018/09/23 18:38	upstream	328c6333ba3d	37079712	.config	log	report	syz
ci-upstream-kasan-gce	2018/09/23 15:46	upstream	328c6333ba3d	37079712	.config	log	report	syz
ci-upstream-kasan-gce-root	2018/09/23 12:59	upstream	328c6333ba3d	37079712	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2018/09/23 09:57	upstream	328c6333ba3d	37079712	.config	log	report	syz
ci-upstream-kasan-gce-selinux-root	2018/09/23 08:45	upstream	328c6333ba3d	37079712	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2018/09/23 01:12	upstream	10dc890d4228	37079712	.config	log	report	syz
ci-upstream-kasan-gce-selinux-root	2018/09/23 01:10	upstream	10dc890d4228	37079712	.config	log	report	syz
ci-upstream-kasan-gce-root	2018/09/23 01:08	upstream	10dc890d4228	37079712	.config	log	report	syz
ci-upstream-kasan-gce-386	2018/10/15 22:43	upstream	f0a7d1883d9f	8cd30605	.config	log	report	syz
ci-upstream-kasan-gce-386	2018/09/23 01:13	upstream	10dc890d4228	37079712	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2018/10/15 21:35	linux-next	ca0591d03a2d	8cd30605	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2018/09/23 13:26	linux-next	46c163a036b4	37079712	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2018/09/23 01:10	linux-next	46c163a036b4	37079712	.config	log	report	syz
ci-upstream-kasan-gce-root	2019/03/26 15:30	upstream	a3ac7917b730	55684ce1	.config	log	report
ci-upstream-kasan-gce-root	2019/03/26 07:32	upstream	a3ac7917b730	55684ce1	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/03/22 17:36	upstream	0939221e6468	dce6e62f	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/03/21 23:57	upstream	0939221e6468	dce6e62f	.config	log	report
ci-upstream-kasan-gce-root	2019/03/21 07:03	upstream	54c490164523	427ea487	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/03/19 11:51	upstream	9e98c678c2d6	46264c32	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/03/19 11:36	upstream	9e98c678c2d6	46264c32	.config	log	report
ci-upstream-kasan-gce-root	2019/03/18 19:40	upstream	9e98c678c2d6	4656beca	.config	log	report
ci-upstream-kasan-gce-root	2019/03/07 12:18	upstream	f90d64483ebd	8c085c5e	.config	log	report
ci-upstream-kasan-gce	2019/03/07 11:16	upstream	f90d64483ebd	8c085c5e	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/03/06 03:41	upstream	63bdf4284c38	16559f86	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/03/06 02:07	upstream	63bdf4284c38	16559f86	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/03/04 16:56	upstream	1c163f4c7b3f	7c693b52	.config	log	report
ci-upstream-kasan-gce-root	2019/03/04 13:28	upstream	1c163f4c7b3f	7c693b52	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/03/01 22:09	upstream	7d762d69145a	68d9e495	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/03/01 10:41	upstream	7d762d69145a	8a4b3a6b	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/28 07:55	upstream	7d762d69145a	34ec456b	.config	log	report
ci-upstream-kasan-gce-root	2019/02/24 00:56	upstream	e60b5f79bd75	7a06e792	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/02/22 11:02	upstream	8a61716ff2ab	7ff74a98	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/20 19:36	upstream	2137397c92ae	c95f0707	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/15 20:41	upstream	cb5b020a8d38	f6f233c0	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/13 02:03	upstream	57902dc0670c	1eedba36	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/12 23:51	upstream	57902dc0670c	6ecc6d0f	.config	log	report
ci-upstream-kasan-gce-root	2019/02/12 00:20	upstream	aa0c38cf39de	65a0d619	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/11 14:21	upstream	d13937116f1e	73f5f452	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/09 06:57	upstream	46c291e277f9	fa6c7b70	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/09 04:33	upstream	74e96711e337	fa6c7b70	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/08 12:00	upstream	d47e3da17592	aa4feb03	.config	log	report
ci-upstream-kasan-gce-root	2019/02/07 23:09	upstream	b0314565da2b	aa4feb03	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/07 11:48	upstream	b0314565da2b	aa4feb03	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/02/07 08:27	upstream	8834f5600cf3	d25487bc	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/02/06 04:55	upstream	8834f5600cf3	d672172c	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/02/05 11:32	upstream	8834f5600cf3	d672172c	.config	log	report
ci-upstream-kasan-gce-root	2019/01/30 18:57	upstream	1c0490ce9022	aa432daf	.config	log	report
ci-upstream-kasan-gce-root	2019/01/29 05:17	upstream	4aa9fc2a435a	aa432daf	.config	log	report
ci-upstream-kasan-gce-root	2019/01/26 23:59	upstream	ba6069759381	c73f090a	.config	log	report
ci-upstream-kasan-gce-386	2019/03/23 00:31	upstream	fd1f297b794c	3361bde5	.config	log	report
ci-upstream-kasan-gce-386	2019/03/01 22:32	upstream	7d762d69145a	68d9e495	.config	log	report
ci-upstream-kasan-gce-386	2019/02/16 16:18	upstream	5ded5871030e	f42dee6d	.config	log	report
ci-upstream-kasan-gce-386	2019/02/14 18:17	upstream	1f947a7a011f	76dd003f	.config	log	report
ci-upstream-kasan-gce-386	2019/02/14 02:26	upstream	1f947a7a011f	0a49c954	.config	log	report
ci-upstream-kasan-gce-386	2019/02/12 02:48	upstream	aa0c38cf39de	65a0d619	.config	log	report
ci-upstream-kasan-gce-386	2019/02/07 13:00	upstream	b0314565da2b	aa4feb03	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/03/19 02:16	linux-next	b99981945914	46264c32	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/03/17 08:35	linux-next	cf08baa29613	bab43553	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/03/15 10:54	linux-next	cf08baa29613	bab43553	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/03/15 01:39	linux-next	cf08baa29613	d72db19b	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/03/03 09:18	linux-next	c63e9e91a254	1c0e457a	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/02/14 01:16	linux-next	c4f3ef3eb53f	0a49c954	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/02/09 06:51	linux-next	a46228f6598a	fa6c7b70	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/02/06 13:11	linux-next	1a82ba1c69e3	d25487bc	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/01/27 09:13	linux-next	494367cb57c9	c73f090a	.config	log	report
ci-upstream-mmots-kasan-gce	2017/12/27 19:23	mmots	37759fa6d0fa	09c8f4c0	.config	log	report
ci-upstream-next-kasan-gce	2017/12/19 07:06	linux-next	6084b576dca2	1c4160ef	.config	log	report