upstream test error: WARNING in rcu_tasks_verify_work_fn

Status: upstream: reported on 2026/09/15 00:01
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+9d7ab3bc11055d9740f5@syzkaller.appspotmail.com
First crash: 4d06h, last: 4d06h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
32748719 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ upstream test error: WARNING in rcu_tasks_verify_work_fn 2026/09/12 00:32 2026/09/12 00:32 2026/09/12 01:01 6816f32e
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] upstream test error: WARNING in rcu_tasks_verify_work_fn 0 (1) 2026/09/15 00:01

Sample crash report:
call_rcu_tasks() has failed boot-time tests.
rcu_tasks: RTGS_WAIT_SCAN_HOLDOUTS(6) since 24 g:5 i:0 kCuUP l:25 
------------[ cut here ]------------
ret < 0
WARNING: kernel/rcu/tasks.h:1541 at rcu_tasks_verify_self_tests kernel/rcu/tasks.h:1541 [inline], CPU#1: kworker/1:2/56
WARNING: kernel/rcu/tasks.h:1541 at rcu_tasks_verify_work_fn+0x1b6/0x270 kernel/rcu/tasks.h:1553, CPU#1: kworker/1:2/56
Modules linked in:
CPU: 1 UID: 0 PID: 56 Comm: kworker/1:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events rcu_tasks_verify_work_fn
RIP: 0010:rcu_tasks_verify_self_tests kernel/rcu/tasks.h:1541 [inline]
RIP: 0010:rcu_tasks_verify_work_fn+0x1b6/0x270 kernel/rcu/tasks.h:1553
Code: 80 3c 10 00 0f 85 b5 00 00 00 48 8b 35 9b 91 7d 0c b9 64 00 00 00 bf 08 00 00 00 48 c7 c2 a0 8a 99 9b e8 ad 6c e2 ff eb 97 90 <0f> 0b 90 eb 91 48 89 df e8 7d 82 8f 00 e9 69 ff ff ff 48 89 df e8
RSP: 0000:ffffc9000110fbb0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff8edeb8a8 RCX: 0000000000000000
RDX: 1ffffffff1dbd715 RSI: ffffffff81e97409 RDI: fffff52000221f49
RBP: 1ffff92000221f76 R08: 0000000000000007 R09: 0000000000000000
R10: 8000000000000000 R11: 0000000000000001 R12: 0000000000000bb8
R13: 00000000ffffffff R14: 0000000000000001 R15: ffffffff8edeb8a8
FS:  0000000000000000(0000) GS:ffff888123c60000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000eb96000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
 process_scheduled_works kernel/workqueue.c:3479 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/10 23:18 upstream 08df884136f1 1fe56c0a .config console log report [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto upstream test error: WARNING in rcu_tasks_verify_work_fn
* Struck through repros no longer work on HEAD.