INFO: task can't die in pipe_release (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d03154e8 Add linux-next specific files for 20210128
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1360311b500000
kernel config: https://syzkaller.appspot.com/x/.config?x=6953ffb584722a1
dashboard link: https://syzkaller.appspot.com/bug?extid=0f45bf8c63785914be1e
compiler: gcc (GCC) 10.1.0-syz 20200507
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0f45bf...@syzkaller.appspotmail.com

INFO: task syz-executor.4:16676 can't die for more than 147 seconds.
task:syz-executor.4 state:D stack:29048 pid:16676 ppid: 8473 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:4326 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5077
schedule+0xcf/0x270 kernel/sched/core.c:5156
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:5215
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x81a/0x1110 kernel/locking/mutex.c:1103
__pipe_lock fs/pipe.c:87 [inline]
pipe_release+0x49/0x320 fs/pipe.c:703
__fput+0x283/0x920 fs/file_table.c:280
task_work_run+0xdd/0x190 kernel/task_work.c:140
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417b71
RSP: 002b:00007ffc01d8d550 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000417b71
RDX: 0000001b2ca20000 RSI: ffffffff8903e45e RDI: 0000000000000003
RBP: 0000000000000001 R08: ffffffff8132e020 R09: 000000009ef3fe36
R10: 00007ffc01d8d630 R11: 0000000000000293 R12: 000000000119ca00
R13: 000000000119ca00 R14: 00000000000003e8 R15: 000000000119c0dc
INFO: task syz-executor.4:16676 blocked for more than 151 seconds.
Not tainted 5.11.0-rc5-next-20210128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4 state:D stack:29048 pid:16676 ppid: 8473 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:4326 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5077
schedule+0xcf/0x270 kernel/sched/core.c:5156
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:5215
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x81a/0x1110 kernel/locking/mutex.c:1103
__pipe_lock fs/pipe.c:87 [inline]
pipe_release+0x49/0x320 fs/pipe.c:703
__fput+0x283/0x920 fs/file_table.c:280
task_work_run+0xdd/0x190 kernel/task_work.c:140
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417b71
RSP: 002b:00007ffc01d8d550 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000417b71
RDX: 0000001b2ca20000 RSI: ffffffff8903e45e RDI: 0000000000000003
RBP: 0000000000000001 R08: ffffffff8132e020 R09: 000000009ef3fe36
R10: 00007ffc01d8d630 R11: 0000000000000293 R12: 000000000119ca00
R13: 000000000119ca00 R14: 00000000000003e8 R15: 000000000119c0dc


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[syzbot]

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