[syzbot] WARNING in io_poll_double_wake

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    1216f02e Add linux-next specific files for 20210415
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12a322b1d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3491b04113499f81
dashboard link: https://syzkaller.appspot.com/bug?extid=f2aca089e6f77e5acd46
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=154654c5d00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=102c0319d00000

The issue was bisected to:

commit b69de288e913030082bed3a324ddc58be6c1e983
Author: Jens Axboe <axboe@xxxxxxxxx>
Date:   Wed Mar 17 14:37:41 2021 +0000

    io_uring: allow events and user_data update of running poll requests

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12c4b2b6d00000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=11c4b2b6d00000
console output: https://syzkaller.appspot.com/x/log.txt?x=16c4b2b6d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f2aca089e6f77e5acd46@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: b69de288e913 ("io_uring: allow events and user_data update of running poll requests")

------------[ cut here ]------------
WARNING: CPU: 1 PID: 8455 at fs/io_uring.c:1494 req_ref_put fs/io_uring.c:1494 [inline]
WARNING: CPU: 1 PID: 8455 at fs/io_uring.c:1494 req_ref_put fs/io_uring.c:1492 [inline]
WARNING: CPU: 1 PID: 8455 at fs/io_uring.c:1494 io_poll_double_wake+0x516/0x770 fs/io_uring.c:4943
Modules linked in:
CPU: 1 PID: 8455 Comm: syz-executor676 Not tainted 5.12.0-rc7-next-20210415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:req_ref_put fs/io_uring.c:1494 [inline]
RIP: 0010:req_ref_put fs/io_uring.c:1492 [inline]
RIP: 0010:io_poll_double_wake+0x516/0x770 fs/io_uring.c:4943
Code: e8 1f 4c dc ff f0 ff 4d 5c 0f 94 c3 31 ff 89 de e8 7f 92 97 ff 84 db b8 01 00 00 00 0f 84 57 fc ff ff 89 04 24 e8 ba 8b 97 ff <0f> 0b 8b 04 24 e9 45 fc ff ff e8 ab 8b 97 ff 49 89 ec e9 83 fb ff
RSP: 0018:ffffc9000172fad8 EFLAGS: 00010093
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88801adbb900 RSI: ffffffff81dcec86 RDI: 0000000000000003
RBP: ffff8880125ac8c0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff81dcec71 R11: 0000000000000000 R12: ffff8880125ac91c
R13: 0000000000000000 R14: ffff8880125ac8f0 R15: ffff888014ed6820
FS:  00000000015a73c0(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004af100 CR3: 000000001eb33000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __wake_up_common+0x147/0x650 kernel/sched/wait.c:108
 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:138
 tty_ldisc_lock+0x55/0xb0 drivers/tty/tty_ldisc.c:336
 tty_ldisc_hangup+0x200/0x680 drivers/tty/tty_ldisc.c:752
 __tty_hangup.part.0+0x40a/0x870 drivers/tty/tty_io.c:639
 __tty_hangup drivers/tty/tty_io.c:595 [inline]
 tty_vhangup drivers/tty/tty_io.c:712 [inline]
 tty_ioctl+0xf6a/0x1600 drivers/tty/tty_io.c:2746
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl fs/ioctl.c:1055 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4408a9
Code: 1b 01 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 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 c4 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeb1a62488 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004408a9
RDX: 0000000000000000 RSI: 0000000000005437 RDI: 0000000000000005
RBP: 00007ffeb1a624b8 R08: 000000000000000e R09: 00007ffeb1a624e0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeb1a624e0
R13: 0000000000000000 R14: 00000000004af018 R15: 0000000000400488


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