possible deadlock in __sock

possible deadlock in __sock_release
Status: upstream: reported C repro on 2020/08/31 20:58
Reported-by: syzbot+8e467b009209f1fcf666@syzkaller.appspotmail.com
First crash: 415d, last: 103d

Cause bisection: introduced by (bisect log) [merge commit]:
commit edea44f5872a14d0e8698e0e0e540320833db9cb
Author: Jiri Kosina <jkosina@suse.cz>
Date: Wed Feb 12 13:20:41 2020 +0000

Merge branch 'for-5.7/core' into for-next

Crash: WARNING: ODEBUG bug in __do_softirq (log)
Repro: C syz .config

Fix bisection: fixed by (bisect log) :
commit 8fb4792f091e608a0a1d353dfdf07ef55a719db5
Author: Paolo Abeni <pabeni@redhat.com>
Date: Tue Jul 20 13:08:40 2021 +0000

ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.19	possible deadlock in __sock_release	C		done	57446	78d	340d	1/1	fixed on 2021/08/30 09:32

Sample crash report:

======================================================
WARNING: possible circular locking dependency detected
5.13.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor501/8626 is trying to acquire lock:
ffff888039ffec10 (
&sb->s_type->i_mutex_key#13
){+.+.}-{3:3}
, at: inode_lock include/linux/fs.h:774 [inline]
, at: __sock_release+0x86/0x280 net/socket.c:647

but task is already holding lock:
ffff888028d5b520
 (sk_lock-AF_TIPC
){+.+.}-{0:0}
, at: lock_sock include/net/sock.h:1613 [inline]
, at: sock_setsockopt+0x1e3/0x2490 net/core/sock.c:980

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (
sk_lock-AF_TIPC){+.+.}-{0:0}
:
       lock_sock_nested+0xca/0x120 net/core/sock.c:3168
       lock_sock include/net/sock.h:1613 [inline]
       tipc_release+0xc2/0x1a00 net/tipc/socket.c:637
       __sock_release+0xcd/0x280 net/socket.c:648
       sock_close+0x18/0x20 net/socket.c:1300
       __fput+0x288/0x920 fs/file_table.c:280
       task_work_run+0xdd/0x1a0 kernel/task_work.c:164
       tracehook_notify_resume include/linux/tracehook.h:189 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
       exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:209
       __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
       syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
       do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (
&sb->s_type->i_mutex_key#13
){+.+.}-{3:3}
:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add kernel/locking/lockdep.c:3174 [inline]
       validate_chain kernel/locking/lockdep.c:3789 [inline]
       __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015
       lock_acquire kernel/locking/lockdep.c:5625 [inline]
       lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
       down_write+0x92/0x150 kernel/locking/rwsem.c:1406
       inode_lock include/linux/fs.h:774 [inline]
       __sock_release+0x86/0x280 net/socket.c:647
       sock_close+0x18/0x20 net/socket.c:1300
       __fput+0x288/0x920 fs/file_table.c:280
       task_work_run+0xdd/0x1a0 kernel/task_work.c:164
       get_signal+0x1bb0/0x2150 kernel/signal.c:2569
       arch_do_signal_or_restart+0x2a9/0x1eb0 arch/x86/kernel/signal.c:789
       handle_signal_work kernel/entry/common.c:148 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
       exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209
       __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
       syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
       do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sk_lock-AF_TIPC
);
                               lock(
&sb->s_type->i_mutex_key#13
);
                               lock(
sk_lock-AF_TIPC);
  lock(&sb->s_type->i_mutex_key
#13);

 *** DEADLOCK ***

1 lock held by syz-executor501/8626:
 #0: ffff888028d5b520
 (sk_lock-AF_TIPC
){+.+.}-{0:0}
, at: lock_sock include/net/sock.h:1613 [inline]
, at: sock_setsockopt+0x1e3/0x2490 net/core/sock.c:980

stack backtrace:
CPU: 1 PID: 8626 Comm: syz-executor501 Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2131
 check_prev_add kernel/locking/lockdep.c:3051 [inline]
 check_prevs_add kernel/locking/lockdep.c:3174 [inline]
 validate_chain kernel/locking/lockdep.c:3789 [inline]
 __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015
 lock_acquire kernel/locking/lockdep.c:5625 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
 down_write+0x92/0x150 kernel/locking/rwsem.c:1406
 inode_lock include/linux/fs.h:774 [inline]
 __sock_release+0x86/0x280 net/socket.c:647
 sock_close+0x18/0x20 net/socket.c:1300
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 get_signal+0x1bb0/0x2150 kernel/signal.c:2569
 arch_do_signal_or_restart+0x2a9/0x1eb0 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x44ed49
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 18 00 00 90 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f943c11b208 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: fffffffffffffff2 RBX: 00000000004cd4a8 RCX: 000000000044ed49
RDX: 0000000000000025 RSI: 0000000000000001 RDI: 0000000000000005
RBP: 00000000004cd4a0 R08: 0000000000000008 R09: 0000000000000000
R10: 00000000200001c0 R11: 0000000000000246 R12: 00000000004cd4ac
R13: 00007ffc4809da7f R14: 00007f943c11b300 R15: 0000000000022000

Crashes (2728):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-net-this-kasan-gce	2021/07/06 03:55	net	c6c205ed442e	55aa55c2	.config	log	report	syz	C		possible deadlock in __sock_release
ci-upstream-linux-next-kasan-gce-root	2020/09/07 21:40	linux-next	7a6956579ce6	abf9ba4f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/09/06 15:00	linux-next	7a6956579ce6	abf9ba4f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/31 09:48	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/30 14:20	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/30 13:00	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/30 12:39	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/30 12:00	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/29 01:53	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/28 23:59	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/28 22:52	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/28 21:23	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/28 13:16	linux-next	b36c969764ab	816e0689	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2020/08/29 11:28	linux-next	b36c969764ab	d5a3ae1f	.config	log	report	syz
ci-upstream-bpf-next-kasan-gce	2020/09/22 14:55	bpf-next	a8a717963fe5	3e8f6c27	.config	log	report			info
ci-upstream-net-kasan-gce	2020/09/07 16:06	net-next	02a20d4fef3d	abf9ba4f	.config	log	report
ci-upstream-net-kasan-gce	2020/08/27 20:48	net-next	50aba46c234e	816e0689	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 17:27	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 17:15	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 16:09	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 15:17	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 14:37	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 12:39	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 12:05	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 11:23	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 11:17	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 10:16	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 09:45	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 09:18	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 08:47	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 08:07	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 07:35	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 07:01	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 05:28	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 05:06	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 03:46	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 03:46	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 02:42	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 01:52	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/08 00:23	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 23:42	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 23:09	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 22:41	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 22:41	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 21:09	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 20:08	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 19:24	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 19:17	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 18:13	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 18:05	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 17:02	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 14:00	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 12:37	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 11:04	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 10:04	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 09:30	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 08:40	linux-next	7a6956579ce6	abf9ba4f	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/09/07 07:16	linux-next	7a6956579ce6	abf9ba4f	.config	log	report