Subject: Re: [syzbot] WARNING in __cleanup_sighand

From: syzbot <[email-masked]>
Date: Wed, 19 Jan 2022 22:37:16 -0800

syzbot has found a reproducer for the following issue on:

HEAD commit:    1d1df41c5a33 Merge tag 'f2fs-for-5.17-rc1' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=135e0637b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a8db61f521ec3155
dashboard link: https://syzkaller.appspot.com/bug?extid=985a662ba46639a7897f
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13381237b00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15160867b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

------------[ cut here ]------------
WARNING: CPU: 1 PID: 3600 at kernel/sched/wait.c:245 __wake_up_pollfree+0x1c7/0x1d0 kernel/sched/wait.c:246
Modules linked in:
CPU: 1 PID: 3600 Comm: syz-executor582 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__wake_up_pollfree+0x1c7/0x1d0 kernel/sched/wait.c:245
Code: 0d 00 00 c6 44 08 0f 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 a0 00 00 00 75 13 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b eb a7 e8 f0 89 b1 08 55 41 57 41 56 41 55 41 54 53 48 83 ec
RSP: 0018:ffffc90001aaf760 EFLAGS: 00010016
RAX: ffff8880787693f0 RBX: 0000000000000046 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: ffffc90001aaf848 R08: dffffc0000000000 R09: ffffed10046325d2
R10: ffffed10046325d2 R11: 0000000000000000 R12: 0000000000000000
R13: ffffc90001aaf7a0 R14: 1ffff92000355ef4 R15: ffff888023192ec8
FS:  000055555695d300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200000c0 CR3: 000000002374c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __cleanup_sighand+0x48/0xa0 kernel/fork.c:1588
 __exit_signal kernel/exit.c:159 [inline]
 release_task+0x115f/0x15d0 kernel/exit.c:200
 wait_task_zombie kernel/exit.c:1121 [inline]
 wait_consider_task+0x1995/0x3020 kernel/exit.c:1348
 do_wait_thread kernel/exit.c:1411 [inline]
 do_wait+0x291/0x9d0 kernel/exit.c:1528
 kernel_wait4+0x2a3/0x3c0 kernel/exit.c:1691
 __do_sys_wait4 kernel/exit.c:1719 [inline]
 __se_sys_wait4 kernel/exit.c:1715 [inline]
 __x64_sys_wait4+0x130/0x1e0 kernel/exit.c:1715
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fb66a5bb386
Code: 0f 1f 40 00 31 c9 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 49 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 11 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 90 48 83 ec 28 89 54 24 14 48 89 74 24
RSP: 002b:00007ffe9339ed58 EFLAGS: 00000246 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 000000000000ce97 RCX: 00007fb66a5bb386
RDX: 0000000040000001 RSI: 00007ffe9339ed74 RDI: 00000000ffffffff
RBP: 0000000000001284 R08: 00007ffe933e2080 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 431bde82d7b634db
R13: 00007ffe9339ed74 R14: 0000000000000000 R15: 0000000000000000
 </TASK>