syzbot

 sign-in | mailing list | source | docs
🐞 Open [852]
🐞 Fixed [138]
🐞 Invalid [974]
⬇ Missing Backports [75]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in batadv_nc_worker

Status: upstream: reported C repro on 2023/07/06 06:16
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+13306b743f5eee80aab3@syzkaller.appspotmail.com
First crash: 909d, last: 1d13h
Fix commit to backport (bisect log) :
tree: upstream
commit 8c21ab1bae945686c602c5bfa4e3f3352c2452c5
Author: Eric Dumazet <edumazet@google.com>
Date: Tue Aug 29 12:35:41 2023 +0000

  net/sched: fq_pie: avoid stalls in fq_pie_timer()

[report pending]
  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: INFO: rcu detected stall in corrupted (log)
Repro: C syz .config
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2023/09/18 linux-6.1.y (ToT) 09045dae0d90 C [report] INFO: rcu detected stall in corrupted
2023/09/18 upstream (ToT) 2cf0f7156238 C Didn't crash
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in batadv_nc_worker cgroups mm 1 7 2219d 2220d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in batadv_nc_worker (2) mm 1 4 2184d 2184d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in batadv_nc_worker (3) batman 1 C done inconclusive 585 106d 1917d 0/29 upstream: reported C repro on 2020/10/01 10:35
linux-5.15 INFO: rcu detected stall in batadv_nc_worker origin:lts-only 1 C done 304 1d00h 931d 0/3 upstream: reported C repro on 2023/06/13 20:27
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2023/11/06 15:29 7h44m fix candidate upstream OK (1) job log
2023/10/25 07:11 2h37m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4441/1:b..l
	(detected by 0, t=10503 jiffies, g=11021, q=90 ncpus=2)
task:kworker/u4:7    state:R  running task     stack:26464 pid:4441  ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0xe1/0x490 kernel/locking/lockdep.c:5633
Code: 74 bc 0c 0f 83 8c 01 00 00 45 89 f4 41 c1 ee 06 4a 8d 3c f5 a8 6a 1f 8e be 08 00 00 00 e8 77 0e 6e 00 4c 0f a3 25 27 72 bc 0c <73> 0d e8 f8 1b 08 00 84 c0 0f 84 18 02 00 00 48 c7 c0 64 9f 1f 8e
RSP: 0018:ffffc90003537ac0 EFLAGS: 00000257
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8162f879
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e1f6aa8
RBP: ffffc90003537bc8 R08: dffffc0000000000 R09: fffffbfff1c3ed56
R10: fffffbfff1c3ed56 R11: 1ffffffff1c3ed55 R12: 0000000000000001
R13: 1ffff920006a6f64 R14: 0000000000000000 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xeb/0x600 net/batman-adv/network-coding.c:719
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: rcu_preempt kthread starved for 10528 jiffies! g11021 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 4506 Comm: syz.0.25 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 8f 41 f7 48 89 df e8 e6 54 42 f7 e8 31 48 65 f7 fb bf 01 00 00 00 <e8> 76 cd 35 f7 65 8b 05 f7 84 e0 75 85 c0 74 02 5b c3 e8 44 96 de
RSP: 0018:ffffc90003617b98 EFLAGS: 00000282
RAX: 2e21e019a6801700 RBX: ffff8880276aef00 RCX: 2e21e019a6801700
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: 0000000000000001
RBP: ffff8880276af398 R08: dffffc0000000000 R09: ffffed1004ed5de1
R10: ffffed1004ed5de1 R11: 1ffff11004ed5de0 R12: 1ffff11004ed5e73
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
FS:  000055556d3c9500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000005cce8000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x1163/0x1350 kernel/signal.c:2874
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdef338f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4d683888 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fdef35e5fa0 RCX: 00007fdef338f749
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fdef3413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdef35e5fa0 R14: 00007fdef35e5fa0 R15: 0000000000000004
 </TASK>

Crashes (223):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/05 14:55 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2023/09/18 20:52 linux-6.1.y 09045dae0d90 0b6a67ac .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/11/24 08:25 linux-6.1.y f6e38ae624cf 4fb8ef37 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/29 04:48 linux-6.1.y 8e6e2188d949 fd2207e7 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/15 08:01 linux-6.1.y 3db754f56897 e2beed91 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/04/12 09:53 linux-6.1.y 420102835862 0bd6db41 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/01/26 21:24 linux-6.1.y 75cefdf153f5 9fbd772e .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/01/26 11:00 linux-6.1.y 75cefdf153f5 9fbd772e .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/30 02:50 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/30 00:11 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/29 14:46 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/20 07:08 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/20 02:36 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/18 02:15 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/13 01:08 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/11 18:35 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/06 08:50 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/06 05:42 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/05 09:46 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/03 09:58 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/12/02 12:39 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/11/30 00:08 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/11/26 12:33 linux-6.1.y f6e38ae624cf 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/11/24 21:36 linux-6.1.y f6e38ae624cf bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/11/21 23:56 linux-6.1.y f6e38ae624cf 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/11/20 21:46 linux-6.1.y f6e38ae624cf 2cc4c24a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/11/04 21:58 linux-6.1.y f6e38ae624cf 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/29 22:31 linux-6.1.y f6e38ae624cf fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/27 22:03 linux-6.1.y 8e6e2188d949 fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/26 18:40 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/23 02:25 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/21 17:24 linux-6.1.y 8e6e2188d949 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/20 11:56 linux-6.1.y 8e6e2188d949 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/19 02:53 linux-6.1.y c2fda4b3f577 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/18 08:26 linux-6.1.y c2fda4b3f577 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/07 09:52 linux-6.1.y 882efbdd9d34 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/03 15:35 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/10/01 22:11 linux-6.1.y 7b34dc04e4ff a1859138 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/28 08:13 linux-6.1.y 7b34dc04e4ff 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/27 20:27 linux-6.1.y 7b34dc04e4ff 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/15 18:46 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/08 12:38 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/06 00:30 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/05 16:01 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/02 03:58 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/09/02 00:11 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/08/31 12:06 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/08/29 20:06 linux-6.1.y f89b6e15694c 3e1beec6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/08/28 06:58 linux-6.1.y 0bc96de781b4 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/08/25 10:24 linux-6.1.y 0bc96de781b4 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/08/21 22:38 linux-6.1.y 0bc96de781b4 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2025/08/09 16:39 linux-6.1.y 3594f306da12 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
2024/07/21 11:12 linux-6.1.y 9b3f9a5b12dc b88348e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in batadv_nc_worker
2025/09/24 14:21 linux-6.1.y 363a599da6d9 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: rcu detected stall in batadv_nc_worker
2023/07/06 06:15 linux-6.1.y 0f4ac6b4c5f0 ba5dba36 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in batadv_nc_worker
* Struck through repros no longer work on HEAD.