* [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2)
@ 2026-05-27 6:52 syzbot
2026-11-15 6:26 ` syzbot
2026-11-15 15:22 ` Ming Lei
0 siblings, 2 replies; 6+ messages in thread
From: syzbot @ 2026-05-27 6:52 UTC (permalink / raw)
To: axboe, io-uring, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 6a97c4d5262d Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17a41ea6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e327ee9a867dd6b9
dashboard link: https://syzkaller.appspot.com/bug?extid=b0d54b9e81de55179e47
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5cc8b6debcbd/disk-6a97c4d5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/649698f0231f/vmlinux-6a97c4d5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b297958f355b/bzImage-6a97c4d5.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com
------------[ cut here ]------------
time_after(jiffies, warn_timeout)
WARNING: io_uring/io-wq.c:1370 at io_wq_exit_workers io_uring/io-wq.c:1370 [inline], CPU#1: syz.1.3756/22484
WARNING: io_uring/io-wq.c:1370 at io_wq_put_and_exit+0x36c/0x9d0 io_uring/io-wq.c:1399, CPU#1: syz.1.3756/22484
Modules linked in:
CPU: 1 UID: 0 PID: 22484 Comm: syz.1.3756 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:io_wq_exit_workers io_uring/io-wq.c:1370 [inline]
RIP: 0010:io_wq_put_and_exit+0x36c/0x9d0 io_uring/io-wq.c:1399
Code: 00 00 0f 85 7d 05 00 00 48 8b 15 9f 3c 4c 09 4d 89 e7 31 ff 49 29 d7 4c 89 fe e8 cf f6 13 fd 4d 85 ff 79 aa e8 e5 fb 13 fd 90 <0f> 0b 90 eb 9f e8 da fb 13 fd 4c 8d 63 08 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc900077af8c0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888033fdb000 RCX: ffffffff84f4b5f1
RDX: ffff888030d4ca00 RSI: ffffffff84f4b5fb RDI: ffff888030d4ca00
RBP: fffffbfff1c81e50 R08: 0000000000000007 R09: 0000000000000000
R10: ffffffffffffe7c3 R11: 0000000000000000 R12: 0000000100027def
R13: 0000000000001b58 R14: ffff888033fdb018 R15: ffffffffffffe7c3
FS: 00007ff97ac796c0(0000) GS:ffff88812446a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4b79c90b9b CR3: 0000000037235000 CR4: 00000000003526f0
Call Trace:
<TASK>
io_uring_clean_tctx+0x114/0x180 io_uring/tctx.c:248
io_uring_cancel_generic+0x7b9/0x810 io_uring/cancel.c:657
io_uring_files_cancel include/linux/io_uring.h:20 [inline]
do_exit+0x344/0x2af0 kernel/exit.c:916
do_group_exit+0xd5/0x2a0 kernel/exit.c:1119
get_signal+0x20ff/0x2210 kernel/signal.c:3037
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x8b/0x4f0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x706/0x860 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff979d9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff97ac79028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: 0000000000018ff8 RBX: 00007ff97a015fa0 RCX: 00007ff979d9ce59
RDX: 0000000000018ff8 RSI: 0000200000009b80 RDI: 0000000000000003
RBP: 00007ff979e32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff97a016038 R14: 00007ff97a015fa0 R15: 00007ffc1552e588
</TASK>
---
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 syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2)
2026-05-27 6:52 [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2) syzbot
@ 2026-11-15 6:26 ` syzbot
2026-11-15 15:10 ` Jens Axboe
2026-11-15 15:10 ` Jens Axboe
2026-11-15 15:22 ` Ming Lei
1 sibling, 2 replies; 6+ messages in thread
From: syzbot @ 2026-11-15 6:26 UTC (permalink / raw)
To: axboe, elzeigel, io-uring, linux-block, linux-kernel,
linux-kernel, syzkaller-bugs, tom.leiming, zcgao
syzbot has found a reproducer for the following issue on:
HEAD commit: aacb77975041 Merge tag 'ovl-fixes-7.4-rc3' of git://git.ke..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1105ee3d580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1cf189394a856f11
dashboard link: https://syzkaller.appspot.com/bug?extid=b0d54b9e81de55179e47
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1093cb69580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com
------------[ cut here ]------------
time_after(jiffies, warn_timeout)
WARNING: io_uring/io-wq.c:1482 at io_wq_exit_workers io_uring/io-wq.c:1482 [inline], CPU#0: syz-executor273/6014
WARNING: io_uring/io-wq.c:1482 at io_wq_put_and_exit+0x372/0x9d0 io_uring/io-wq.c:1511, CPU#0: syz-executor273/6014
Modules linked in:
CPU: 0 UID: 0 PID: 6014 Comm: syz-executor273 Tainted: G S syzkaller #0 PREEMPT(full)
Tainted: [S]=CPU_OUT_OF_SPEC
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:io_wq_exit_workers io_uring/io-wq.c:1482 [inline]
RIP: 0010:io_wq_put_and_exit+0x372/0x9d0 io_uring/io-wq.c:1511
Code: 00 00 0f 85 7d 05 00 00 48 8b 15 e9 74 8a 0a 4d 89 e7 31 ff 49 29 d7 4c 89 fe e8 f9 fd d7 fc 4d 85 ff 79 aa e8 4f 03 d8 fc 90 <0f> 0b 90 eb 9f e8 44 03 d8 fc 4c 8d 63 08 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc90003abfb10 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888038fb1000 RCX: 0000000000000000
RDX: ffff88802b0d2580 RSI: ffffffff85367db1 RDI: 0000000000000007
RBP: fffffbfff1f81e50 R08: 0000000000000000 R09: ffffffffffffd785
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000100001f9b
R13: 0000000000000064 R14: ffff888038fb1018 R15: ffffffffffffd785
FS: 00007f00678c46c0(0000) GS:ffff88812246c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe270457d0 CR3: 0000000023abe000 CR4: 00000000003526f0
Call Trace:
<TASK>
io_uring_clean_tctx+0x117/0x180 io_uring/tctx.c:261
io_uring_cancel_generic+0xa9e/0xb00 io_uring/cancel.c:771
io_uring_files_cancel include/linux/io_uring.h:52 [inline]
do_exit+0x344/0x2a00 kernel/exit.c:920
__do_sys_exit kernel/exit.c:1090 [inline]
__se_sys_exit kernel/exit.c:1088 [inline]
__x64_sys_exit+0x42/0x50 kernel/exit.c:1088
x64_sys_call+0x156c/0x1570 arch/x86/include/generated/asm/syscalls_64.h:61
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x7b0 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f00678f9a99
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f00678c3fd8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f00678f9a99
RDX: 00007f00678f9086 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00007f00670c3140 R08: 0000000000000000 R09: 0000001000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f00670c3004
R13: 00007f006796b0e5 R14: 0000000000000006 R15: 00007f00678c40e0
</TASK>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2)
2026-11-15 6:26 ` syzbot
@ 2026-11-15 15:10 ` Jens Axboe
2026-11-15 15:10 ` Jens Axboe
1 sibling, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2026-11-15 15:10 UTC (permalink / raw)
To: syzbot, elzeigel, io-uring, linux-block, linux-kernel,
linux-kernel, syzkaller-bugs, tom.leiming, zcgao
On 11/14/26 11:26 PM, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: aacb77975041 Merge tag 'ovl-fixes-7.4-rc3' of git://git.ke..
> git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> console output: https://syzkaller.appspot.com/x/log.txt?x=1105ee3d580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=1cf189394a856f11
> dashboard link: https://syzkaller.appspot.com/bug?extid=b0d54b9e81de55179e47
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1093cb69580000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> time_after(jiffies, warn_timeout)
> WARNING: io_uring/io-wq.c:1482 at io_wq_exit_workers io_uring/io-wq.c:1482 [inline], CPU#0: syz-executor273/6014
> WARNING: io_uring/io-wq.c:1482 at io_wq_put_and_exit+0x372/0x9d0 io_uring/io-wq.c:1511, CPU#0: syz-executor273/6014
> Modules linked in:
> CPU: 0 UID: 0 PID: 6014 Comm: syz-executor273 Tainted: G S syzkaller #0 PREEMPT(full)
> Tainted: [S]=CPU_OUT_OF_SPEC
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
> RIP: 0010:io_wq_exit_workers io_uring/io-wq.c:1482 [inline]
> RIP: 0010:io_wq_put_and_exit+0x372/0x9d0 io_uring/io-wq.c:1511
> Code: 00 00 0f 85 7d 05 00 00 48 8b 15 e9 74 8a 0a 4d 89 e7 31 ff 49 29 d7 4c 89 fe e8 f9 fd d7 fc 4d 85 ff 79 aa e8 4f 03 d8 fc 90 <0f> 0b 90 eb 9f e8 44 03 d8 fc 4c 8d 63 08 48 b8 00 00 00 00 00 fc
> RSP: 0018:ffffc90003abfb10 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffff888038fb1000 RCX: 0000000000000000
> RDX: ffff88802b0d2580 RSI: ffffffff85367db1 RDI: 0000000000000007
> RBP: fffffbfff1f81e50 R08: 0000000000000000 R09: ffffffffffffd785
> R10: 0000000000000001 R11: 0000000000000000 R12: 0000000100001f9b
> R13: 0000000000000064 R14: ffff888038fb1018 R15: ffffffffffffd785
> FS: 00007f00678c46c0(0000) GS:ffff88812246c000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ffe270457d0 CR3: 0000000023abe000 CR4: 00000000003526f0
> Call Trace:
> <TASK>
> io_uring_clean_tctx+0x117/0x180 io_uring/tctx.c:261
> io_uring_cancel_generic+0xa9e/0xb00 io_uring/cancel.c:771
> io_uring_files_cancel include/linux/io_uring.h:52 [inline]
> do_exit+0x344/0x2a00 kernel/exit.c:920
> __do_sys_exit kernel/exit.c:1090 [inline]
> __se_sys_exit kernel/exit.c:1088 [inline]
> __x64_sys_exit+0x42/0x50 kernel/exit.c:1088
> x64_sys_call+0x156c/0x1570 arch/x86/include/generated/asm/syscalls_64.h:61
> do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
> do_syscall_64+0x123/0x7b0 arch/x86/entry/syscall_64.c:89
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f00678f9a99
> Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 d0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f00678c3fd8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
> RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f00678f9a99
> RDX: 00007f00678f9086 RSI: 0000000000000001 RDI: 0000000000000000
> RBP: 00007f00670c3140 R08: 0000000000000000 R09: 0000001000000008
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f00670c3004
> R13: 00007f006796b0e5 R14: 0000000000000006 R15: 00007f00678c40e0
> </TASK>
There's nothing wrong here. Your reproducer has a stuck request, which is an
IORING_OP_OPENAT on a fuse mount that never responds. Hence it's stuck and
can't get canceled. This btw is different than the original report,
which was the usual silly "let's generate giant reads against MSR" where
MSR reads are really slow, and yes that can then also take a while to
complete if they are already executing.
IOW, they are both bogus, and I think the only sane recourse here is to
change that WARN_ON_ONCE() to a pr_warn_once() with the necessary
details. The entry point to the io-wq exit can be gleaned from a bunch
of minor things like task etc, so won't really lose us anything. But
it'd prevent noise like this report in the future.
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2)
2026-11-15 6:26 ` syzbot
2026-11-15 15:10 ` Jens Axboe
@ 2026-11-15 15:10 ` Jens Axboe
1 sibling, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2026-11-15 15:10 UTC (permalink / raw)
To: syzbot, elzeigel, io-uring, linux-block, linux-kernel,
linux-kernel, syzkaller-bugs, tom.leiming, zcgao
On 11/14/26 11:26 PM, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: aacb77975041 Merge tag 'ovl-fixes-7.4-rc3' of git://git.ke..
> git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> console output: https://syzkaller.appspot.com/x/log.txt?x=1105ee3d580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=1cf189394a856f11
> dashboard link: https://syzkaller.appspot.com/bug?extid=b0d54b9e81de55179e47
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1093cb69580000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> time_after(jiffies, warn_timeout)
> WARNING: io_uring/io-wq.c:1482 at io_wq_exit_workers io_uring/io-wq.c:1482 [inline], CPU#0: syz-executor273/6014
> WARNING: io_uring/io-wq.c:1482 at io_wq_put_and_exit+0x372/0x9d0 io_uring/io-wq.c:1511, CPU#0: syz-executor273/6014
> Modules linked in:
> CPU: 0 UID: 0 PID: 6014 Comm: syz-executor273 Tainted: G S syzkaller #0 PREEMPT(full)
> Tainted: [S]=CPU_OUT_OF_SPEC
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
> RIP: 0010:io_wq_exit_workers io_uring/io-wq.c:1482 [inline]
> RIP: 0010:io_wq_put_and_exit+0x372/0x9d0 io_uring/io-wq.c:1511
> Code: 00 00 0f 85 7d 05 00 00 48 8b 15 e9 74 8a 0a 4d 89 e7 31 ff 49 29 d7 4c 89 fe e8 f9 fd d7 fc 4d 85 ff 79 aa e8 4f 03 d8 fc 90 <0f> 0b 90 eb 9f e8 44 03 d8 fc 4c 8d 63 08 48 b8 00 00 00 00 00 fc
> RSP: 0018:ffffc90003abfb10 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffff888038fb1000 RCX: 0000000000000000
> RDX: ffff88802b0d2580 RSI: ffffffff85367db1 RDI: 0000000000000007
> RBP: fffffbfff1f81e50 R08: 0000000000000000 R09: ffffffffffffd785
> R10: 0000000000000001 R11: 0000000000000000 R12: 0000000100001f9b
> R13: 0000000000000064 R14: ffff888038fb1018 R15: ffffffffffffd785
> FS: 00007f00678c46c0(0000) GS:ffff88812246c000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ffe270457d0 CR3: 0000000023abe000 CR4: 00000000003526f0
> Call Trace:
> <TASK>
> io_uring_clean_tctx+0x117/0x180 io_uring/tctx.c:261
> io_uring_cancel_generic+0xa9e/0xb00 io_uring/cancel.c:771
> io_uring_files_cancel include/linux/io_uring.h:52 [inline]
> do_exit+0x344/0x2a00 kernel/exit.c:920
> __do_sys_exit kernel/exit.c:1090 [inline]
> __se_sys_exit kernel/exit.c:1088 [inline]
> __x64_sys_exit+0x42/0x50 kernel/exit.c:1088
> x64_sys_call+0x156c/0x1570 arch/x86/include/generated/asm/syscalls_64.h:61
> do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
> do_syscall_64+0x123/0x7b0 arch/x86/entry/syscall_64.c:89
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f00678f9a99
> Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 d0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f00678c3fd8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
> RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f00678f9a99
> RDX: 00007f00678f9086 RSI: 0000000000000001 RDI: 0000000000000000
> RBP: 00007f00670c3140 R08: 0000000000000000 R09: 0000001000000008
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f00670c3004
> R13: 00007f006796b0e5 R14: 0000000000000006 R15: 00007f00678c40e0
> </TASK>
There's nothing wrong here. Your reproducer has a stuck request, which is an
IORING_OP_OPENAT on a fuse mount that never responds. Hence it's stuck and
can't get canceled. This btw is different than the original report,
which was the usual silly "let's generate giant reads against MSR" where
MSR reads are really slow, and yes that can then also take a while to
complete if they are already executing.
IOW, they are both bogus, and I think the only sane recourse here is to
change that WARN_ON_ONCE() to a pr_warn_once() with the necessary
details. The entry point to the io-wq exit can be gleaned from a bunch
of minor things like task etc, so won't really lose us anything. But
it'd prevent noise like this report in the future.
#syz invalid
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2)
2026-05-27 6:52 [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2) syzbot
2026-11-15 6:26 ` syzbot
@ 2026-11-15 15:22 ` Ming Lei
2026-11-15 15:26 ` Jens Axboe
1 sibling, 1 reply; 6+ messages in thread
From: Ming Lei @ 2026-11-15 15:22 UTC (permalink / raw)
To: syzbot; +Cc: axboe, io-uring, linux-kernel, syzkaller-bugs
On Wed, May 27, 2026 at 1:53 AM syzbot
<syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 6a97c4d5262d Merge tag 'for-linus' of git://git.kernel.org..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17a41ea6580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=e327ee9a867dd6b9
> dashboard link: https://syzkaller.appspot.com/bug?extid=b0d54b9e81de55179e47
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/5cc8b6debcbd/disk-6a97c4d5.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/649698f0231f/vmlinux-6a97c4d5.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/b297958f355b/bzImage-6a97c4d5.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> time_after(jiffies, warn_timeout)
> WARNING: io_uring/io-wq.c:1370 at io_wq_exit_workers io_uring/io-wq.c:1370 [inline], CPU#1: syz.1.3756/22484
> WARNING: io_uring/io-wq.c:1370 at io_wq_put_and_exit+0x36c/0x9d0 io_uring/io-wq.c:1399, CPU#1: syz.1.3756/22484
> Modules linked in:
> CPU: 1 UID: 0 PID: 22484 Comm: syz.1.3756 Tainted: G L syzkaller #0 PREEMPT(full)
> Tainted: [L]=SOFTLOCKUP
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
> RIP: 0010:io_wq_exit_workers io_uring/io-wq.c:1370 [inline]
> RIP: 0010:io_wq_put_and_exit+0x36c/0x9d0 io_uring/io-wq.c:1399
> Code: 00 00 0f 85 7d 05 00 00 48 8b 15 9f 3c 4c 09 4d 89 e7 31 ff 49 29 d7 4c 89 fe e8 cf f6 13 fd 4d 85 ff 79 aa e8 e5 fb 13 fd 90 <0f> 0b 90 eb 9f e8 da fb 13 fd 4c 8d 63 08 48 b8 00 00 00 00 00 fc
> RSP: 0018:ffffc900077af8c0 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffff888033fdb000 RCX: ffffffff84f4b5f1
> RDX: ffff888030d4ca00 RSI: ffffffff84f4b5fb RDI: ffff888030d4ca00
> RBP: fffffbfff1c81e50 R08: 0000000000000007 R09: 0000000000000000
> R10: ffffffffffffe7c3 R11: 0000000000000000 R12: 0000000100027def
> R13: 0000000000001b58 R14: ffff888033fdb018 R15: ffffffffffffe7c3
> FS: 00007ff97ac796c0(0000) GS:ffff88812446a000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f4b79c90b9b CR3: 0000000037235000 CR4: 00000000003526f0
> Call Trace:
> <TASK>
> io_uring_clean_tctx+0x114/0x180 io_uring/tctx.c:248
> io_uring_cancel_generic+0x7b9/0x810 io_uring/cancel.c:657
> io_uring_files_cancel include/linux/io_uring.h:20 [inline]
> do_exit+0x344/0x2af0 kernel/exit.c:916
> do_group_exit+0xd5/0x2a0 kernel/exit.c:1119
> get_signal+0x20ff/0x2210 kernel/signal.c:3037
> arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
> __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
> exit_to_user_mode_loop+0x8b/0x4f0 kernel/entry/common.c:98
> __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
> syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
> syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
> do_syscall_64+0x706/0x860 arch/x86/entry/syscall_64.c:100
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7ff979d9ce59
> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ff97ac79028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> RAX: 0000000000018ff8 RBX: 00007ff97a015fa0 RCX: 00007ff979d9ce59
> RDX: 0000000000018ff8 RSI: 0000200000009b80 RDI: 0000000000000003
> RBP: 00007ff979e32d6f R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ff97a016038 R14: 00007ff97a015fa0 R15: 00007ffc1552e588
> </TASK>
It should be fixed by the following patch:
https://lore.kernel.org/linux-block/20260930042335.16199-1-zcgao@amazon.com/
Thanks,
Ming Lei
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2)
2026-11-15 15:22 ` Ming Lei
@ 2026-11-15 15:26 ` Jens Axboe
0 siblings, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2026-11-15 15:26 UTC (permalink / raw)
To: Ming Lei, syzbot; +Cc: io-uring, linux-kernel, syzkaller-bugs
On 11/15/26 8:22 AM, Ming Lei wrote:
> On Wed, May 27, 2026 at 1:53?AM syzbot
> <syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com> wrote:
>>
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: 6a97c4d5262d Merge tag 'for-linus' of git://git.kernel.org..
>> git tree: upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=17a41ea6580000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=e327ee9a867dd6b9
>> dashboard link: https://syzkaller.appspot.com/bug?extid=b0d54b9e81de55179e47
>> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
>>
>> Unfortunately, I don't have any reproducer for this issue yet.
>>
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/5cc8b6debcbd/disk-6a97c4d5.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/649698f0231f/vmlinux-6a97c4d5.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/b297958f355b/bzImage-6a97c4d5.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+b0d54b9e81de55179e47@syzkaller.appspotmail.com
>>
>> ------------[ cut here ]------------
>> time_after(jiffies, warn_timeout)
>> WARNING: io_uring/io-wq.c:1370 at io_wq_exit_workers io_uring/io-wq.c:1370 [inline], CPU#1: syz.1.3756/22484
>> WARNING: io_uring/io-wq.c:1370 at io_wq_put_and_exit+0x36c/0x9d0 io_uring/io-wq.c:1399, CPU#1: syz.1.3756/22484
>> Modules linked in:
>> CPU: 1 UID: 0 PID: 22484 Comm: syz.1.3756 Tainted: G L syzkaller #0 PREEMPT(full)
>> Tainted: [L]=SOFTLOCKUP
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
>> RIP: 0010:io_wq_exit_workers io_uring/io-wq.c:1370 [inline]
>> RIP: 0010:io_wq_put_and_exit+0x36c/0x9d0 io_uring/io-wq.c:1399
>> Code: 00 00 0f 85 7d 05 00 00 48 8b 15 9f 3c 4c 09 4d 89 e7 31 ff 49 29 d7 4c 89 fe e8 cf f6 13 fd 4d 85 ff 79 aa e8 e5 fb 13 fd 90 <0f> 0b 90 eb 9f e8 da fb 13 fd 4c 8d 63 08 48 b8 00 00 00 00 00 fc
>> RSP: 0018:ffffc900077af8c0 EFLAGS: 00010293
>> RAX: 0000000000000000 RBX: ffff888033fdb000 RCX: ffffffff84f4b5f1
>> RDX: ffff888030d4ca00 RSI: ffffffff84f4b5fb RDI: ffff888030d4ca00
>> RBP: fffffbfff1c81e50 R08: 0000000000000007 R09: 0000000000000000
>> R10: ffffffffffffe7c3 R11: 0000000000000000 R12: 0000000100027def
>> R13: 0000000000001b58 R14: ffff888033fdb018 R15: ffffffffffffe7c3
>> FS: 00007ff97ac796c0(0000) GS:ffff88812446a000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f4b79c90b9b CR3: 0000000037235000 CR4: 00000000003526f0
>> Call Trace:
>> <TASK>
>> io_uring_clean_tctx+0x114/0x180 io_uring/tctx.c:248
>> io_uring_cancel_generic+0x7b9/0x810 io_uring/cancel.c:657
>> io_uring_files_cancel include/linux/io_uring.h:20 [inline]
>> do_exit+0x344/0x2af0 kernel/exit.c:916
>> do_group_exit+0xd5/0x2a0 kernel/exit.c:1119
>> get_signal+0x20ff/0x2210 kernel/signal.c:3037
>> arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
>> __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
>> exit_to_user_mode_loop+0x8b/0x4f0 kernel/entry/common.c:98
>> __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
>> syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
>> syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
>> do_syscall_64+0x706/0x860 arch/x86/entry/syscall_64.c:100
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> RIP: 0033:0x7ff979d9ce59
>> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007ff97ac79028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
>> RAX: 0000000000018ff8 RBX: 00007ff97a015fa0 RCX: 00007ff979d9ce59
>> RDX: 0000000000018ff8 RSI: 0000200000009b80 RDI: 0000000000000003
>> RBP: 00007ff979e32d6f R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
>> R13: 00007ff97a016038 R14: 00007ff97a015fa0 R15: 00007ffc1552e588
>> </TASK>
>
> It should be fixed by the following patch:
>
> https://lore.kernel.org/linux-block/20260930042335.16199-1-zcgao@amazon.com/
Not the posted reproducer, that has nothing to do with ublk. But yes you
could certainly make one with ublk as well. In practice any of these
"exit is slow, use WARN_ON_ONCE()" will always be triggerable, as the
fuse case in the reproducer. That doesn't mean that the above isn't a
bug and should not be fixed in ublk, just that it is an instance of
something that can trigger the slow exit WARN_ON_ONCE().
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-11-15 15:26 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-05-27 6:52 [syzbot] [io-uring?] WARNING in io_wq_put_and_exit (2) syzbot
2026-11-15 6:26 ` syzbot
2026-11-15 15:10 ` Jens Axboe
2026-11-15 15:10 ` Jens Axboe
2026-11-15 15:22 ` Ming Lei
2026-11-15 15:26 ` Jens Axboe
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