INFO: task hung in pipe_release

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 54fa720a ANDROID: xfrm: remove in_compat_syscall() checks
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=1042facc600000
kernel config: https://syzkaller.appspot.com/x/.config?x=2d1497d4b2cea8f4
dashboard link: https://syzkaller.appspot.com/bug?extid=5f4eae74b834b4ffe29b
compiler: gcc (GCC) 9.0.0 20181231 (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: syzbot+5f4eae...@syzkaller.appspotmail.com

INFO: task syz-executor.5:8028 blocked for more than 140 seconds.
Not tainted 4.14.134+ #22
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5 D29008 8028 1863 0x80000002
Call Trace:
schedule+0x92/0x1c0 kernel/sched/core.c:3498
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
__pipe_lock fs/pipe.c:88 [inline]
pipe_release+0x49/0x240 fs/pipe.c:583
__fput+0x25e/0x710 fs/file_table.c:210
task_work_run+0x125/0x1a0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x9cb/0x2a20 kernel/exit.c:874

Showing all locks held in the system:
1 lock held by khungtaskd/23:
#0: (tasklist_lock){.+.+}, at: [<00000000de999506>]
debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
2 locks held by getty/1758:
#0: (&tty->ldisc_sem){++++}, at: [<000000009a468f40>]
tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ea8bec3c>]
n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.5/8017:
#0: (&pipe->mutex/1){+.+.}, at: [<00000000da57d21c>] pipe_lock_nested
fs/pipe.c:67 [inline]
#0: (&pipe->mutex/1){+.+.}, at: [<00000000da57d21c>] pipe_lock+0x58/0x70
fs/pipe.c:75
1 lock held by syz-executor.5/8028:
#0: (&pipe->mutex/1){+.+.}, at: [<0000000074cc3c6b>] __pipe_lock
fs/pipe.c:88 [inline]
#0: (&pipe->mutex/1){+.+.}, at: [<0000000074cc3c6b>]
pipe_release+0x49/0x240 fs/pipe.c:583

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.134+ #22
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xca/0x134 lib/dump_stack.c:53
nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1628 Comm: rs:main Q:Reg Not tainted 4.14.134+ #22
task: 0000000022ca417f task.stack: 0000000012bea41b
RIP: 0010:__lock_acquire+0x9da/0x42e0 kernel/locking/lockdep.c:3365
RSP: 0018:ffff8881d4b6f0e0 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1ffffffff5796050 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffff8881d4b6f2b0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffffaaa2ca0b R12: 0000000000000000
R13: 0000000000000001 R14: ffff8881d4900000 R15: ffffffffabcb0280
FS: 00007fa2f2224700(0000) GS:ffff8881dbb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c42d1c3000 CR3: 00000001d60b2002 CR4: 00000000001606a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x12b/0x360 kernel/locking/lockdep.c:3991
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:160
debug_object_activate+0x131/0x4f0 lib/debugobjects.c:434
debug_work_activate kernel/workqueue.c:493 [inline]
__queue_work+0x47/0xdd0 kernel/workqueue.c:1402
__queue_delayed_work+0x1f3/0x2a0 kernel/workqueue.c:1545
queue_delayed_work_on+0x9e/0xa0 kernel/workqueue.c:1581
queue_delayed_work include/linux/workqueue.h:506 [inline]
kblockd_schedule_delayed_work+0x26/0x30 block/blk-core.c:3241
blk_mq_kick_requeue_list block/blk-mq.c:736 [inline]
blk_mq_add_to_requeue_list+0x297/0x340 block/blk-mq.c:730
blk_flush_queue_rq+0x76/0x2e0 block/blk-flush.c:138
blk_kick_flush block/blk-flush.c:341 [inline]
blk_flush_complete_seq+0x9aa/0x1040 block/blk-flush.c:215
blk_insert_flush+0x4b0/0x9c0 block/blk-flush.c:484
blk_mq_sched_insert_flush block/blk-mq-sched.c:352 [inline]
blk_mq_sched_insert_request+0x48b/0x590 block/blk-mq-sched.c:367
blk_mq_make_request+0x501/0x19c0 block/blk-mq.c:1750
generic_make_request block/blk-core.c:2227 [inline]
generic_make_request+0x212/0x880 block/blk-core.c:2171
submit_bio+0xa7/0x390 block/blk-core.c:2301
submit_bio_wait+0xff/0x170 block/bio.c:1012
blkdev_issue_flush+0x218/0x320 block/blk-flush.c:531
ext4_sync_file+0xb2f/0x1250 fs/ext4/fsync.c:157
vfs_fsync_range+0x106/0x260 fs/sync.c:196
generic_write_sync include/linux/fs.h:2697 [inline]
ext4_file_write_iter+0x83c/0xd60 fs/ext4/file.c:275
call_write_iter include/linux/fs.h:1788 [inline]
new_sync_write fs/read_write.c:471 [inline]
__vfs_write+0x401/0x5a0 fs/read_write.c:484
vfs_write+0x17f/0x4d0 fs/read_write.c:546
SYSC_write fs/read_write.c:594 [inline]
SyS_write+0x102/0x250 fs/read_write.c:586
do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
Code: 00 0f 85 13 23 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48
b8 00 00 00 00 00 fc ff df 4c 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 96 25
00 00 49 81 3f 00 e6 06 ab 0f 84 59 f7 ff ff 83 fe


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.