WARNING in task_participate_group_stop

Status: premoderation: reported C repro on 2025/09/15 18:43
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+4d12e6a4ee1d58207e12@syzkaller.appspotmail.com
First crash: 413d, last: 59d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/09/18 lts (merge base) d90ecb2b1308 C [report] WARNING in task_participate_group_stop
2025/09/18 upstream (ToT) 8b789f2b7602 C [report] WARNING in task_participate_group_stop
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 WARNING in task_participate_group_stop -1 syz, C inconclusive 8 1504d 2527d 0/1 upstream: reported C repro on 2019/12/02 14:36
upstream WARNING in task_participate_group_stop (2) prio:low kernel -1 syz, C inconclusive unreliable 25 171d 3109d 29/29 fixed on 2026/07/15 08:27
android-414 WARNING in task_participate_group_stop -1 syz, C 2 2798d 2761d 0/1 public: reported C repro on 2019/04/12 00:01
android-44 WARNING in task_participate_group_stop (2) -1 syz, C 4 2798d 2760d 0/2 public: reported C repro on 2019/04/13 00:00
android-49 WARNING in task_participate_group_stop -1 syz, C 15 3218d 3375d 2/3 fixed on 2018/02/06 12:55
upstream WARNING in task_participate_group_stop -1 syz, C 29 3275d 3290d 4/29 fixed on 2018/02/02 04:39
linux-4.19 WARNING in task_participate_group_stop -1 syz, C error 11 1506d 2527d 0/1 upstream: reported C repro on 2019/12/02 13:46
android-44 WARNING in task_participate_group_stop -1 syz, C 10 3227d 3234d 2/2 fixed on 2018/02/06 10:09
android-49 WARNING in task_participate_group_stop (2) -1 syz, C 11 2527d 2759d 0/3 public: reported C repro on 2019/04/14 00:00
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/11/01 22:38 20m retest repro android16-6.12 no crash job log log
2026/11/01 22:38 20m retest repro android16-6.12 no crash job log log
2026/11/01 22:38 20m retest repro android16-6.12 no crash job log log
2026/08/19 05:44 10m retest repro android16-6.12 report job log log
2026/08/19 05:44 9m retest repro android16-6.12 report job log log
2026/08/19 05:44 10m retest repro android16-6.12 report job log log
2026/05/25 15:34 24m retest repro android16-6.12 log
2026/05/11 13:29 1h06m retest repro android16-6.12 report log
2026/03/06 11:40 16m retest repro android16-6.12 report log
2026/02/17 01:44 10m retest repro android16-6.12 report log

Sample crash report:
process '/newroot/41/file0' started with executable stack
------------[ cut here ]------------
WARNING: CPU: 1 PID: 663 at kernel/signal.c:375 task_participate_group_stop+0x242/0x300 kernel/signal.c:375
Modules linked in:
CPU: 1 UID: 0 PID: 663 Comm: file0 Not tainted syzkaller #0 a94c0ccc1001594cac83a8f4adefd4b76cd2ae72
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:task_participate_group_stop+0x242/0x300 kernel/signal.c:375
Code: 74 08 4c 89 f7 e8 be 16 8d 00 4d 89 2e f0 83 44 24 fc 00 4c 89 f7 be 15 00 00 00 e8 88 9f 10 00 e9 aa fe ff ff e8 0e 3b 34 00 <0f> 0b 42 0f b6 04 2b 84 c0 0f 85 8c 00 00 00 45 8b 3e e9 ee fe ff
RSP: 0018:ffffc9000e377c30 EFLAGS: 00010083
RAX: ffffffff81533c52 RBX: 1ffff110238b3bce RCX: 0000000000080000
RDX: ffffc90002685000 RSI: 0000000000041d03 RDI: 0000000000041d04
RBP: ffffc9000e377c60 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001c6ef90 R12: ffff88811c59de00
R13: dffffc0000000000 R14: ffff88811c59de70 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000ff96010b CR3: 000000011b416000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 do_signal_stop+0x63e/0x840 kernel/signal.c:2516
 get_signal+0xa7a/0x1490 kernel/signal.c:2780
 arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x57/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0023:0x2ca
Code: Unable to access opcode bytes at 0x2a0.
RSP: 002b:00000000ff960030 EFLAGS: 00000202 ORIG_RAX: 000000000000000b
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
---[ end trace 0000000000000000 ]---

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/04 18:31 android16-6.12 8e7315ce7b79 f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in task_participate_group_stop
2026/07/19 22:29 android16-6.12 0fd55a309793 72524a66 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in task_participate_group_stop
2026/07/19 21:45 android16-6.12 0fd55a309793 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in task_participate_group_stop
2026/02/20 10:19 android16-6.12 879c70c90804 17d780d6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in task_participate_group_stop
2025/09/15 18:42 android16-6.12 78993dd6e8f8 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in task_participate_group_stop
* Struck through repros no longer work on HEAD.