INFO: rcu detected stall in task_numa_work (2)

Status: upstream: reported C repro on 2025/01/04 04:47
Subsystems: mm bpf
[Documentation on labels]
Reported-by: syzbot+06d48cbf3e767907cec2@syzkaller.appspotmail.com
First crash: 858d, last: 71d
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (8)
ID Workflow Result Correct Bug Created Started Finished Revision
5f2c553e assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/09/09 01:43 2026/09/09 01:43 2026/09/09 02:07 243b72f1
60f56a23 assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/08/09 12:56 2026/08/09 12:56 2026/08/09 13:23 5d63f80b
691a48b9 assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/07/08 01:07 2026/07/08 01:07 2026/07/08 01:30 93f57954
0691197b assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/06/22 01:02 2026/06/22 01:02 2026/06/22 01:21 43bfcdb0
e43de075 assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/06/14 00:48 2026/06/14 00:48 2026/06/14 01:12 4f06757f
16ae16dc assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/06/09 15:34 2026/06/09 15:34 2026/06/09 15:57 c36c07f6
239e5c60 assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/06/02 08:56 2026/06/02 08:56 2026/06/02 09:24 1095583b
1fb2db51 assessment-security 💥 INFO: rcu detected stall in task_numa_work (2) 2026/05/23 23:09 2026/05/23 23:09 2026/05/23 23:35 c69befb3
▶ ▼ Discussions (5)
Title Replies (including bot) Last reply
[syzbot] Monthly bpf report (Jul 2026) 0 (1) 2026/07/23 04:32
[syzbot] Monthly bpf report (Jun 2026) 0 (1) 2026/06/22 04:32
[syzbot] Monthly bpf report (May 2026) 0 (1) 2026/05/18 04:32
[syzbot] Monthly bpf report (Feb 2026) 0 (1) 2026/02/06 14:30
[syzbot] [mm?] INFO: rcu detected stall in task_numa_work (2) 0 (1) 2025/01/04 04:47
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in task_numa_work mm 1 2 1128d 1129d 0/29 auto-obsoleted due to no activity on 2023/11/28 14:56
linux-6.1 INFO: rcu detected stall in task_numa_work 1 1 849d 849d 0/3 auto-obsoleted due to no activity on 2024/09/12 14:33
linux-4.19 BUG: soft lockup in task_numa_work 1 1 1764d 1764d 0/1 auto-closed as invalid on 2022/04/01 16:00
▶ ▼ Last patch testing requests (9)
Created Duration User Patch Repo Result
2026/09/19 08:21 49m retest repro net-next no crash job log log
2026/07/05 07:46 56m retest repro net-next log
2026/04/22 07:11 49m retest repro net-next report log
2026/02/11 06:29 32m retest repro net-next report log
2026/02/11 06:24 21m retest repro net-next report log
2025/12/03 05:24 59m retest repro net-next report log
2025/09/23 23:39 25m retest repro net-next report log
2025/07/15 22:47 21m retest repro net-next report log
2025/01/16 00:14 21m retest repro net-next report log
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2025/05/06 10:23 12h04m bisect fix net-next error job log
2025/03/24 01:15 3h15m bisect fix net-next OK (0) job log log
2025/02/19 22:41 3h31m bisect fix net-next OK (0) job log log

Sample crash report:
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5820/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=15697, q=439 ncpus=2)
task:syz-executor    state:R  running task     stack:22904 pid:5820  tgid:5820  ppid:5801   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5260 [inline]
 __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7194
 irqentry_exit+0x17b/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x330 kernel/locking/lockdep.c:5872
Code: 05 bb 32 01 12 83 f8 07 0f 87 a4 02 00 00 48 0f a3 05 46 2e d4 0e 0f 82 6f 02 00 00 8b 35 de 5e d4 0e 85 f6 0f 85 8a 00 00 00 <48> 8b 44 24 30 65 48 2b 05 5d 32 01 12 0f 85 b8 02 00 00 48 83 c4
RSP: 0018:ffffc900042af748 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8dc1f504 RDI: ffffffff8bfa35a0
RBP: ffffffff8e5e32e0 R08: 00000000d1325fbc R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xd1/0x1ea0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x162/0x1e0 mm/page_owner.c:165
 __reset_page_owner+0x84/0x190 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x822/0x1130 mm/page_alloc.c:2973
 discard_slab mm/slub.c:3346 [inline]
 __put_partials+0x127/0x160 mm/slub.c:3886
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:406
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 task_numa_work+0xf50/0x1bb0 kernel/sched/fair.c:3396
 task_work_run+0x150/0x240 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0x100/0x4b0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x4fe/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd50afc3952
RSP: 002b:00007ffd8ff48f80 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: 0000000000000142 RBX: 00007ffd8ff48f80 RCX: 00007fd50afc3952
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffd8ff4910c R08: 0000000000000000 R09: 0000000000000001
R10: 000055555b53f7d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 000000000002dee3 R15: 00007ffd8ff49160
 </TASK>
net_ratelimit: 24500 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (28):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/27 17:54 upstream fcb70a56f4d8 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in task_numa_work
2025/11/05 17:34 upstream 1c353dc8d962 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in task_numa_work
2025/10/11 09:36 upstream 0739473694c4 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in task_numa_work
2025/08/02 18:30 upstream 038d61fd6422 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in task_numa_work
2025/06/01 03:09 upstream 4cb6c8af8591 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in task_numa_work
2025/01/19 14:02 upstream fda5e3f28400 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in task_numa_work
2025/01/18 22:46 upstream fda5e3f28400 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in task_numa_work
2025/01/01 22:22 upstream 56e6a3499e14 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in task_numa_work
2024/12/27 20:21 upstream d6ef8b40d075 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in task_numa_work
2024/10/27 16:51 upstream 850925a8133c 65e8686b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in task_numa_work
2024/10/21 23:45 upstream 42f7652d3eb5 a93682b3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in task_numa_work
2024/08/31 20:00 upstream 1934261d8974 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in task_numa_work
2024/06/24 04:29 upstream 7c16f0a4ed1c edc5149a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in task_numa_work
2024/06/23 13:45 upstream 5f583a3162ff edc5149a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in task_numa_work
2024/05/26 12:03 upstream c13320499ba0 a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in task_numa_work
2026/05/20 18:14 net dc416e32baae 62fb93a2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in task_numa_work
2026/03/12 12:24 net 87f7dff3ec75 4efadf07 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in task_numa_work
2024/11/21 06:22 net 66418447d27b 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in task_numa_work
2026/07/22 23:27 net-next 24d0af194bcc 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2026/06/20 12:31 net-next b85966adbf5d 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2026/05/31 21:53 net-next 841559836550 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2026/05/17 22:52 net-next 627ac78f2741 de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2024/12/31 04:27 net-next 9268abe611b0 d3ccff63 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2024/12/20 12:42 net-next b73e56f16250 1d58202c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2024/12/18 16:17 net-next c1bad69f8baf 1432fc84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2024/12/06 18:25 net-next 51db5c894300 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in task_numa_work
2025/10/18 14:58 linux-next 93f3bab4310d 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in task_numa_work
2024/09/30 05:51 linux-next cea5425829f7 ba29ff75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in task_numa_work
* Struck through repros no longer work on HEAD.