syzbot


BUG: corrupted list in io_poll_remove_entries

Status: upstream: reported C repro on 2026/02/22 09:37
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+c0e02e47f6a27ef4d2b0@syzkaller.appspotmail.com
First crash: 5d09h, last: 5d00h
Bug presence (2)
Date Name Commit Repro Result
2026/02/22 linux-5.15.y (ToT) 3330a8d33e08 C [report] BUG: corrupted list in io_poll_remove_entries
2026/02/22 upstream (ToT) 189f164e573e C Didn't crash
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in io_poll_remove_entries io-uring 19 C done done 751 1058d 1438d 0/29 auto-obsoleted due to no activity on 2023/07/04 23:32
upstream BUG: corrupted list in io_poll_remove_entries media 8 C error 8 6d12h 18d 23/29 upstream: reported C repro on 2026/02/09 18:26
linux-6.1 general protection fault in io_poll_remove_entries 11 C done 21 1062d 1081d 3/3 fixed on 2023/05/02 21:55
upstream KASAN: slab-use-after-free Read in io_poll_remove_entries comedi 19 C 12 213d 223d 29/29 fixed on 2025/09/04 16:57
upstream KASAN: slab-use-after-free Read in io_poll_remove_entries (2) io-uring 19 1 92d 91d 0/29 closed as invalid on 2025/12/19 03:22
linux-5.15 KASAN: use-after-free Read in io_poll_remove_entries origin:lts-only 19 C error 5 187d 214d 0/3 auto-obsoleted due to no activity on 2025/12/08 02:55
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2026/02/24 08:26 1m fix candidate upstream error job log

Sample crash report:
list_del corruption. prev->next should be ffff88807cf588f0, but was ffff88802aa345c8
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:61!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 4373 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__list_del_entry_valid+0x107/0x120 lib/list_debug.c:59
Code: 48 89 de e8 0b 6e c9 05 0f 0b 48 c7 c7 40 fc 79 8a 48 89 de e8 fa 6d c9 05 0f 0b 48 c7 c7 a0 fc 79 8a 48 89 de e8 e9 6d c9 05 <0f> 0b 48 c7 c7 00 fd 79 8a 48 89 de e8 d8 6d c9 05 0f 0b 00 00 cc
RSP: 0018:ffffc900031cfbc8 EFLAGS: 00010046
RAX: 0000000000000054 RBX: ffff88807cf588f0 RCX: 1393da159bc1da00
RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000
RBP: ffff88802aa34588 R08: ffff8880b9033d7f R09: 1ffff110172067af
R10: dffffc0000000000 R11: ffffed10172067b0 R12: dffffc0000000000
R13: ffff88807cf588f0 R14: ffff88802aa345c8 R15: ffff88802aa345c8
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556c39005950 CR3: 000000000c08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __list_del_entry include/linux/list.h:132 [inline]
 list_del_init include/linux/list.h:204 [inline]
 io_poll_remove_entry io_uring/io_uring.c:5579 [inline]
 io_poll_remove_entries+0x193/0x4a0 io_uring/io_uring.c:5606
 io_poll_task_func+0xfe/0x280 io_uring/io_uring.c:5708
 tctx_task_work+0x2d9/0x5e0 io_uring/io_uring.c:2209
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x626/0x20c0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 __do_sys_exit_group kernel/exit.c:1008 [inline]
 __se_sys_exit_group kernel/exit.c:1006 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1006
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f78d04f5629
Code: Unable to access opcode bytes at RIP 0x7f78d04f55ff.
RSP: 002b:00007ffd64067708 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f78d04f5629
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 00007f78d073e3e0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f78d073e3e0 R14: 0000000000000003 R15: 00007ffd640677c0
 </TASK>
Modules linked in:
---[ end trace 690635bab7d10448 ]---
RIP: 0010:__list_del_entry_valid+0x107/0x120 lib/list_debug.c:59
Code: 48 89 de e8 0b 6e c9 05 0f 0b 48 c7 c7 40 fc 79 8a 48 89 de e8 fa 6d c9 05 0f 0b 48 c7 c7 a0 fc 79 8a 48 89 de e8 e9 6d c9 05 <0f> 0b 48 c7 c7 00 fd 79 8a 48 89 de e8 d8 6d c9 05 0f 0b 00 00 cc
RSP: 0018:ffffc900031cfbc8 EFLAGS: 00010046
RAX: 0000000000000054 RBX: ffff88807cf588f0 RCX: 1393da159bc1da00
RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000
RBP: ffff88802aa34588 R08: ffff8880b9033d7f R09: 1ffff110172067af
R10: dffffc0000000000 R11: ffffed10172067b0 R12: dffffc0000000000
R13: ffff88807cf588f0 R14: ffff88802aa345c8 R15: ffff88802aa345c8
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556c39005950 CR3: 000000000c08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/22 11:04 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan BUG: corrupted list in io_poll_remove_entries
2026/02/22 09:40 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan BUG: corrupted list in io_poll_remove_entries
2026/02/22 09:39 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan BUG: corrupted list in io_poll_remove_entries
2026/02/22 09:38 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan BUG: corrupted list in io_poll_remove_entries
2026/02/22 09:36 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan BUG: corrupted list in io_poll_remove_entries
2026/02/22 09:36 linux-5.15.y 3330a8d33e08 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan BUG: corrupted list in io_poll_remove_entries
* Struck through repros no longer work on HEAD.