INFO: task hung in fuse_flush

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ac3af4be Linux 4.19.181
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15f2c0d6d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=4f09908a6dd5ae5f
dashboard link: https://syzkaller.appspot.com/bug?extid=5661ee684e680f0ddbc6

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+5661ee...@syzkaller.appspotmail.com

ieee802154 phy1 wpan1: encryption failed: -22
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
INFO: task syz-executor.1:23886 blocked for more than 140 seconds.
Not tainted 4.19.181-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1 D28648 23886 8144 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
__down_write arch/x86/include/asm/rwsem.h:142 [inline]
down_write+0x4f/0x90 kernel/locking/rwsem.c:72
inode_lock include/linux/fs.h:748 [inline]
fuse_flush+0x1fd/0x5b0 fs/fuse/file.c:421
filp_close+0xb4/0x160 fs/open.c:1162
__close_fd+0x133/0x200 fs/file.c:636
__do_sys_close fs/open.c:1181 [inline]
__se_sys_close fs/open.c:1179 [inline]
__x64_sys_close+0x69/0x100 fs/open.c:1179
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x41927b
Code: Bad RIP value.
RSP: 002b:00007ffd4123a0d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000041927b
RDX: 00000000cb0ebe9e RSI: 0000000009f1f33c RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000001b30b26724
R10: 000511e862d1b6be R11: 0000000000000293 R12: 000000000056c9e0
R13: 000000000056c9e0 R14: 000000000056bf60 R15: 0000000000064ab0
INFO: task syz-executor.1:23903 blocked for more than 140 seconds.
Not tainted 4.19.181-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1 D28592 23903 8144 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common+0x29c/0x470 kernel/sched/completion.c:115
fuse_direct_IO+0x89a/0xe20 fs/fuse/file.c:2942
generic_file_direct_write+0x208/0x4a0 mm/filemap.c:3073
fuse_file_write_iter+0x55d/0x900 fs/fuse/file.c:1216
call_write_iter include/linux/fs.h:1821 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x51b/0x770 fs/read_write.c:487
vfs_write+0x1f3/0x540 fs/read_write.c:549
ksys_write+0x12b/0x2a0 fs/read_write.c:599
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x465f69
Code: Bad RIP value.
RSP: 002b:00007f48e8e17188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465f69
RDX: 0000000000000020 RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 00000000004bfa8f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008
R13: 00007ffd4123a06f R14: 00007f48e8e17300 R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1566:
#0: 000000009690b91c (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by in:imklog/7825:
1 lock held by syz-executor.1/23886:
#0: 00000000a6df3ca4 (&sb->s_type->i_mutex_key#26){+.+.}, at: inode_lock include/linux/fs.h:748 [inline]
#0: 00000000a6df3ca4 (&sb->s_type->i_mutex_key#26){+.+.}, at: fuse_flush+0x1fd/0x5b0 fs/fuse/file.c:421
3 locks held by syz-executor.1/23903:
#0: 00000000efe107ef (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
#1: 00000000711eac14 (sb_writers#19){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline]
#1: 00000000711eac14 (sb_writers#19){.+.+}, at: vfs_write+0x463/0x540 fs/read_write.c:548
#2: 00000000a6df3ca4 (&sb->s_type->i_mutex_key#26){+.+.}, at: inode_lock include/linux/fs.h:748 [inline]
#2: 00000000a6df3ca4 (&sb->s_type->i_mutex_key#26){+.+.}, at: fuse_file_write_iter+0x174/0x900 fs/fuse/file.c:1197

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

NMI backtrace for cpu 1
CPU: 1 PID: 1566 Comm: khungtaskd Not tainted 4.19.181-syzkaller #0
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+0x1fc/0x2ef lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
watchdog+0x991/0xe60 kernel/hung_task.c:287
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8717 Comm: kworker/0:3 Not tainted 4.19.181-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient gc_worker
RIP: 0010:rcu_read_unlock_sched_notrace include/linux/rcupdate.h:771 [inline]
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline]
RIP: 0010:lock_acquire+0x2fb/0x3c0 kernel/locking/lockdep.c:3906
Code: fe ff ff 65 ff 05 95 aa b6 7e 48 8b 05 66 8e c3 09 e8 e9 46 05 00 85 c0 74 09 80 3d 01 3e c3 09 00 74 3f 65 ff 0d 75 aa b6 7e <0f> 85 3e fe ff ff e8 8c 08 b5 ff e9 34 fe ff ff 0f 0b 0f 0b 0f 0b
RSP: 0018:ffff88804c097c00 EFLAGS: 00000086
RAX: 0000000000000000 RBX: ffff8880b2e29b28 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000002 RDI: ffff88804c06eec4
RBP: ffffffff89f85e60 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9f9e5f8000 CR3: 00000000a0dc2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_lock_acquire include/linux/rcupdate.h:242 [inline]
rcu_read_lock include/linux/rcupdate.h:627 [inline]
gc_worker+0x187/0xd90 net/netfilter/nf_conntrack_core.c:1218
process_one_work+0x864/0x1570 kernel/workqueue.c:2152
worker_thread+0x64c/0x1130 kernel/workqueue.c:2295
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

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