* [syzbot ci] Re: io_uring/tctx: add separate lock for list of tctx's in ctx
[not found] <4cffd2b8-e7c9-48df-9207-0df6e3d5c6ce@kernel.dk>
@ 2026-01-01 9:47 ` syzbot ci
0 siblings, 0 replies; only message in thread
From: syzbot ci @ 2026-01-01 9:47 UTC (permalink / raw)
To: axboe, io-uring; +Cc: syzbot, syzkaller-bugs
syzbot ci has tested the following series
[v1] io_uring/tctx: add separate lock for list of tctx's in ctx
https://lore.kernel.org/all/4cffd2b8-e7c9-48df-9207-0df6e3d5c6ce@kernel.dk
* [PATCH] io_uring/tctx: add separate lock for list of tctx's in ctx
and found the following issue:
WARNING in __io_async_cancel
Full report is available here:
https://ci.syzbot.org/series/98951813-facd-4de5-8d20-609c804dc446
***
WARNING in __io_async_cancel
tree: torvalds
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base: f8f9c1f4d0c7a64600e2ca312dec824a0bc2f1da
arch: amd64
compiler: Debian clang version 21.1.8 (++20251202083448+f68f64eb8130-1~exp1~20251202083504.46), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/9e0d952e-d592-4cca-9208-4b87430b4e6f/config
C repro: https://ci.syzbot.org/findings/103d3164-79b9-4a03-bdf3-9bb057961994/c_repro
syz repro: https://ci.syzbot.org/findings/103d3164-79b9-4a03-bdf3-9bb057961994/syz_repro
------------[ cut here ]------------
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff819c3a04>] prepare_to_wait+0x174/0x210 kernel/sched/wait.c:256
WARNING: kernel/sched/core.c:8754 at __might_sleep+0x92/0xf0 kernel/sched/core.c:8750, CPU#1: syz.0.17/5989
Modules linked in:
CPU: 1 UID: 0 PID: 5989 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:__might_sleep+0xac/0xf0 kernel/sched/core.c:8750
Code: 00 00 48 89 3c 24 41 89 f5 4c 8d 35 6e 25 32 0e 43 80 3c 3c 00 74 08 48 89 df e8 0f 31 96 00 48 8b 0b 4c 89 f7 89 ee 48 89 ca <67> 48 0f b9 3a 44 89 ee 48 8b 3c 24 eb b5 44 89 f1 80 e1 07 80 c1
RSP: 0018:ffffc90003c57960 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888112e4ef78 RCX: ffffffff819c3a04
RDX: ffffffff819c3a04 RSI: 0000000000000001 RDI: ffffffff8fc561c0
RBP: 0000000000000001 R08: ffffc90003c57ac7 R09: 0000000000000000
R10: ffffc90003c57aa0 R11: fffff5200078af59 R12: 1ffff110225c9def
R13: 000000000000024f R14: ffffffff8fc561c0 R15: dffffc0000000000
FS: 0000555558120500(0000) GS:ffff8882a9a0f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000001c0 CR3: 00000001165c4000 CR4: 00000000000006f0
Call Trace:
<TASK>
__mutex_lock_common kernel/locking/mutex.c:591 [inline]
__mutex_lock+0x119/0x1340 kernel/locking/mutex.c:776
__io_async_cancel+0x183/0x490 io_uring/cancel.c:188
__io_sync_cancel io_uring/cancel.c:258 [inline]
io_sync_cancel+0x7d2/0x940 io_uring/cancel.c:322
__io_uring_register io_uring/register.c:761 [inline]
__do_sys_io_uring_register io_uring/register.c:921 [inline]
__se_sys_io_uring_register+0xe1b/0x12a0 io_uring/register.c:898
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc802f9acb9
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:00007ffe5ca81768 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab
RAX: ffffffffffffffda RBX: 00007fc803205fa0 RCX: 00007fc802f9acb9
RDX: 00002000000001c0 RSI: 0000000000000018 RDI: 0000000000000003
RBP: 00007fc803008bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc803205fac R14: 00007fc803205fa0 R15: 00007fc803205fa0
</TASK>
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 48 89 3c 24 mov %rdi,(%rsp)
6: 41 89 f5 mov %esi,%r13d
9: 4c 8d 35 6e 25 32 0e lea 0xe32256e(%rip),%r14 # 0xe32257e
10: 43 80 3c 3c 00 cmpb $0x0,(%r12,%r15,1)
15: 74 08 je 0x1f
17: 48 89 df mov %rbx,%rdi
1a: e8 0f 31 96 00 call 0x96312e
1f: 48 8b 0b mov (%rbx),%rcx
22: 4c 89 f7 mov %r14,%rdi
25: 89 ee mov %ebp,%esi
27: 48 89 ca mov %rcx,%rdx
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 44 89 ee mov %r13d,%esi
32: 48 8b 3c 24 mov (%rsp),%rdi
36: eb b5 jmp 0xffffffed
38: 44 89 f1 mov %r14d,%ecx
3b: 80 e1 07 and $0x7,%cl
3e: 80 .byte 0x80
3f: c1 .byte 0xc1
***
If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syzbot@syzkaller.appspotmail.com
---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.
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