syzbot


INFO: rcu detected stall in mrp_periodic_timer

Status: upstream: reported on 2026/06/17 00:42
Reported-by: syzbot+1299c3b55f233016e106@syzkaller.appspotmail.com
First crash: 12d, last: 23h58m
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: rcu detected stall in mrp_periodic_timer 1 2 2308d 2346d 0/1 auto-closed as invalid on 2020/07/01 22:48
upstream INFO: rcu detected stall in mrp_periodic_timer (4) kernel 1 1 1249d 1249d 0/29 auto-obsoleted due to no activity on 2023/04/26 22:06
upstream INFO: rcu detected stall in mrp_periodic_timer (2) net 1 1 2134d 2134d 0/29 auto-closed as invalid on 2020/11/23 04:34
upstream INFO: rcu detected stall in mrp_periodic_timer (5) net 1 2 700d 756d 0/29 auto-obsoleted due to no activity on 2024/10/27 01:42
upstream INFO: rcu detected stall in mrp_periodic_timer net 1 1 2337d 2337d 0/29 auto-closed as invalid on 2020/05/04 02:54
linux-4.19 INFO: rcu detected stall in mrp_periodic_timer 1 3 2282d 2332d 0/1 auto-closed as invalid on 2020/07/28 00:22
upstream INFO: rcu detected stall in mrp_periodic_timer (3) perf 1 1 1636d 1636d 0/29 closed as invalid on 2022/02/08 10:10
linux-6.6 INFO: rcu detected stall in mrp_periodic_timer origin:lts-only 1 C error 1 64d 64d 0/2 upstream: reported C repro on 2026/04/26 04:59
linux-4.19 BUG: soft lockup in mrp_periodic_timer (2) 1 3 1486d 1544d 0/1 auto-obsoleted due to no activity on 2022/10/01 18:22
linux-4.19 BUG: soft lockup in mrp_periodic_timer 1 1 1674d 1674d 0/1 auto-closed as invalid on 2022/03/28 02:00

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P16131
	(detected by 0, t=10502 jiffies, g=72417, q=1923)
task:syz.3.2422      state:R  running task     stack:23024 pid:16131 ppid: 14539 flags:0x0000400c
Call Trace:
 <IRQ>
 sched_show_task+0x459/0x580 kernel/sched/core.c:8659
 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:233 [inline]
 print_other_cpu_stall+0xec5/0x1270 kernel/rcu/tree_stall.h:573
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 8f 04 8f f7 65 8b 05 a0 2b 3f 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0000:ffffc90000007a20 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: f7904457a8bd7100
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001
RBP: ffffc90000007aa0 R08: ffffffff901cb1b7 R09: 1ffffffff2039636
R10: dffffc0000000000 R11: fffffbfff2039637 R12: dffffc0000000000
R13: ffff8880b90280c0 R14: ffff8880b90280c0 R15: 1ffff92000000f44
 __mod_timer+0x925/0xd20 kernel/time/timer.c:1081
 mrp_periodic_timer_arm net/802/mrp.c:617 [inline]
 mrp_periodic_timer+0x1b3/0x1f0 net/802/mrp.c:629
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:finish_lock_switch+0x12f/0x290 kernel/sched/core.c:4804
Code: 83 c7 18 be ff ff ff ff e8 fe 8c 65 08 85 c0 74 46 4d 85 ff 75 62 0f 1f 44 00 00 48 89 df e8 28 f7 6e 08 e8 83 ce 2a 00 fb 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 2f 0e fe ff 43 80 3c 2c
RSP: 0000:ffffc9000312f418 EFLAGS: 00000282
RAX: f7904457a8bd7100 RBX: ffff888078bc5940 RCX: f7904457a8bd7100
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a79c980
RBP: 1ffff11017207613 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
 finish_task_switch+0x12f/0x650 kernel/sched/core.c:4921
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11cb/0x4350 kernel/sched/core.c:6395
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 netif_rx_internal+0x19d/0x550 net/core/dev.c:5018
 netif_rx+0x94/0x380 net/core/dev.c:5044
 ____bpf_clone_redirect net/core/filter.c:2471 [inline]
 bpf_clone_redirect+0x2e1/0x460 net/core/filter.c:2434
 bpf_prog_68f018828fcddb6d+0x5c/0xf1c
 bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x2a8/0x800 net/bpf/test_run.c:119
 bpf_prog_test_run_skb+0x9fb/0x1190 net/bpf/test_run.c:678
 bpf_prog_test_run+0x31c/0x390 kernel/bpf/syscall.c:3374
 __sys_bpf+0x5a5/0x6f0 kernel/bpf/syscall.c:4675
 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4759 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759
 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: 0033:0x7f631e841e59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f631ca9b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f631eabafa0 RCX: 00007f631e841e59
RDX: 0000000000000023 RSI: 0000200000000240 RDI: 000000000000000a
RBP: 00007f631e8d7e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f631eabb038 R14: 00007f631eabafa0 R15: 00007fff28aa1c38
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/28 09:55 linux-5.15.y eceeec79dbc6 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in mrp_periodic_timer
2026/06/17 00:41 linux-5.15.y dc027a595035 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in mrp_periodic_timer
* Struck through repros no longer work on HEAD.