WARNING in kthread_park

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    d1d2220c Add linux-next specific files for 20200924
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15b1918d900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=254e028a642027c
dashboard link: https://syzkaller.appspot.com/bug?extid=e7eea402700c6db193be
compiler:       gcc (GCC) 10.1.0-syz 20200507

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+e7eea402700c6db193be@xxxxxxxxxxxxxxxxxxxxxxxxx

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WARNING: CPU: 1 PID: 28162 at kernel/kthread.c:547 kthread_park+0x17c/0x1b0 kernel/kthread.c:547
Modules linked in:
CPU: 1 PID: 28162 Comm: syz-executor.3 Not tainted 5.9.0-rc6-next-20200924-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kthread_park+0x17c/0x1b0 kernel/kthread.c:547
Code: 2a 04 27 00 0f 0b e9 fb fe ff ff e8 1e 04 27 00 0f 0b e8 17 04 27 00 41 bc da ff ff ff 5b 44 89 e0 5d 41 5c c3 e8 04 04 27 00 <0f> 0b 41 bc f0 ff ff ff eb be e8 f5 03 27 00 0f 0b eb b2 e8 bc 74
RSP: 0018:ffffc90017ebfd50 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888092c0ca00 RCX: ffffffff814e2ccf
RDX: ffff88804f30a040 RSI: ffffffff814e2d6c RDI: 0000000000000007
RBP: ffff88804f46c440 R08: 0000000000000000 R09: ffff888092c0ca07
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffff888096f7d000 R15: 0000000000000000
FS:  0000000002a7e940(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001590004 CR3: 000000020a32f000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 io_sq_thread_park fs/io_uring.c:7145 [inline]
 io_sq_thread_park fs/io_uring.c:7139 [inline]
 io_uring_flush+0x10a6/0x1640 fs/io_uring.c:8596
 filp_close+0xb4/0x170 fs/open.c:1276
 __close_fd+0x2f/0x50 fs/file.c:671
 __do_sys_close fs/open.c:1295 [inline]
 __se_sys_close fs/open.c:1293 [inline]
 __x64_sys_close+0x69/0x100 fs/open.c:1293
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417901
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a4 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fffe4c281e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000417901
RDX: 0000000000000000 RSI: ffffffff8840e309 RDI: 0000000000000003
RBP: 0000000000000001 R08: ffffffff8134e496 R09: 0000000092f8bb6d
R10: 00007fffe4c282d0 R11: 0000000000000293 R12: 000000000118d9c0
R13: 000000000118d9c0 R14: ffffffffffffffff R15: 000000000118cf4c


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