BUG: soft lockup in mrp_join_timer (5)

Status: closed as invalid on 2026/10/06 02:03
Subsystems: kernel
Labels: prio:normal
[Documentation on labels]
First crash: 67d, last: 67d
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
99d0a3bb assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ BUG: soft lockup in mrp_join_timer (5) 2026/08/09 11:27 2026/08/09 11:27 2026/08/09 12:19 5d63f80b
aaaa274c assessment-security 💥 BUG: soft lockup in mrp_join_timer (5) 2026/08/05 00:06 2026/08/05 00:06 2026/08/05 00:06 d4abbeac
▶ ▼ Similar bugs (13)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in mrp_join_timer (4) net 1 10 731d 861d 0/29 auto-obsoleted due to no activity on 2025/01/05 17:43
upstream BUG: soft lockup in mrp_join_timer (4) net 1 1 436d 436d 0/29 closed as invalid on 2025/09/01 08:24
linux-4.14 BUG: soft lockup in mrp_join_timer 1 1 2026d 2026d 0/1 auto-closed as invalid on 2021/07/20 15:25
upstream BUG: soft lockup in mrp_join_timer (2) net 1 1 1103d 1103d 0/29 closed as invalid on 2023/11/01 18:32
linux-4.19 BUG: soft lockup in mrp_join_timer (2) 1 58 1324d 2001d 0/1 upstream: reported on 2021/04/16 18:29
upstream BUG: soft lockup in mrp_join_timer net 1 1 2234d 2230d 0/29 auto-closed as invalid on 2020/10/25 16:14
upstream BUG: soft lockup in mrp_join_timer (3) net 1 2 522d 526d 0/29 closed as invalid on 2025/06/11 12:25
linux-4.19 BUG: soft lockup in mrp_join_timer 1 2 2161d 2176d 0/1 auto-closed as invalid on 2021/03/07 20:15
linux-6.1 INFO: rcu detected stall in mrp_join_timer 1 1 790d 790d 0/3 auto-obsoleted due to no activity on 2024/11/17 18:10
linux-6.1 INFO: rcu detected stall in mrp_join_timer (2) 1 1 319d 319d 0/3 auto-obsoleted due to no activity on 2026/03/04 01:39
linux-6.1 INFO: rcu detected stall in mrp_join_timer (3) 1 3 101d 161d 0/3 auto-obsoleted due to no activity on 2026/10/08 06:20
upstream INFO: rcu detected stall in mrp_join_timer (3) net 1 1 1024d 1024d 0/29 closed as invalid on 2024/02/01 10:31
upstream INFO: rcu detected stall in mrp_join_timer (2) net 1 57 1677d 2427d 0/29 auto-closed as invalid on 2022/07/04 18:27

Sample crash report:
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [kworker/u8:9:5801]
Modules linked in:
irq event stamp: 5724787
hardirqs last  enabled at (5724786): [<ffffffff85a5dd31>] get_random_u32+0x581/0x7d0 drivers/char/random.c:541
hardirqs last disabled at (5724787): [<ffffffff8bb9d31e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1062
softirqs last  enabled at (5724720): [<ffffffff81c8e222>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last  enabled at (5724720): [<ffffffff81c8e222>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last  enabled at (5724720): [<ffffffff81c8e222>] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
softirqs last disabled at (5724729): [<ffffffff81c8e222>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last disabled at (5724729): [<ffffffff81c8e222>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last disabled at (5724729): [<ffffffff81c8e222>] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
CPU: 1 UID: 0 PID: 5801 Comm: kworker/u8:9 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:get_random_u32+0x434/0x7d0 drivers/char/random.c:541
Code: fc 48 85 ed 0f 85 63 01 00 00 e8 37 75 64 fc 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 c5 6f 64 fc 48 85 db 0f 85 84 01 00 00 <e8> 17 75 64 fc 8b 5c 24 38 e8 0e 75 64 fc 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc90000a08b38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff85a5dd43
RDX: ffff888032993e00 RSI: ffffffff85a5dd51 RDI: ffff888032993e00
RBP: 0000000000000200 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b8537160
R13: 1ffff9200014116a R14: ffff8880b8537188 R15: 0000000000000006
FS:  0000000000000000(0000) GS:ffff888123ed9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f34403eb700 CR3: 000000000e994000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 __get_random_u32_below+0x18/0xa0 drivers/char/random.c:555
 get_random_u32_below include/linux/random.h:63 [inline]
 mrp_join_timer_arm+0x1f/0x70 net/802/mrp.c:596
 mrp_join_timer+0x14a/0x180 net/802/mrp.c:612
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x593/0x1870 kernel/smp.c:912
Code: 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 34 9a 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 a8 10 00 00 8b 45 08 31 ff 83 e0 01 41
RSP: 0018:ffffc90004467858 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fdb6f2
RDX: ffff888032993e00 RSI: ffffffff81fdb6cc RDI: ffff888032993e00
RBP: ffff8880b84434e0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed101708869d R14: 0000000000000001 R15: ffff8880b853c9c0
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1077
 on_each_cpu include/linux/smp.h:72 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
 smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x37a/0x550 kernel/jump_label.c:910
 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate mm/kfence/core.c:911 [inline]
 toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:903
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 23540 Comm: syz.4.4717 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x5c/0xc0 kernel/rcu/tree.c:752
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 5c 48 03 1c ed 20 29 47 8e 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 24 8b
RSP: 0018:ffffc90000007d48 EFLAGS: 00000016
RAX: dffffc0000000000 RBX: ffff8880b8433c68 RCX: 0000000000000000
RDX: 1ffff1101708678d RSI: ffffffff8c401a00 RDI: ffffffff8e472920
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f344131c6c0(0000) GS:ffff888123dd9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1d04b7f368 CR3: 000000005a182000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 trace_lock_acquire include/trace/events/lock.h:23 [inline]
 lock_acquire+0x301/0x370 kernel/locking/lockdep.c:5831
 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
 spin_lock include/linux/spinlock.h:342 [inline]
 advance_sched+0xe5/0xd20 net/sched/sch_taprio.c:930
 __run_hrtimer kernel/time/hrtimer.c:2032 [inline]
 __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 b6 0f 29 f6 48 89 df e8 3e 5f 29 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 05 6e 18 f6 65 8b 05 4e 97 a7 08 85 c0 74 16 5b
RSP: 0018:ffffc900040f7778 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff88807e50de80 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff8e1ac5dd RDI: ffffffff8c401a80
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880556a4b40
R13: 0000000000000246 R14: ffff88807e50de68 R15: ffffc900040f78f8
 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline]
 __skb_try_recv_datagram+0x16a/0x500 net/core/datagram.c:267
 __unix_dgram_recvmsg+0x1bc/0xc30 net/unix/af_unix.c:2583
 unix_dgram_recvmsg+0xcd/0x100 net/unix/af_unix.c:2682
 sock_recvmsg_nosec net/socket.c:1126 [inline]
 ____sys_recvmsg+0x5eb/0x670 net/socket.c:2902
 ___sys_recvmsg+0x16a/0x1a0 net/socket.c:2946
 do_recvmmsg+0x2f3/0x740 net/socket.c:3041
 __sys_recvmmsg net/socket.c:3115 [inline]
 __do_sys_recvmmsg net/socket.c:3138 [inline]
 __se_sys_recvmmsg net/socket.c:3131 [inline]
 __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3131
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f344039e019
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:00007f344131c028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f3440626090 RCX: 00007f344039e019
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007f344043500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3440626128 R14: 00007f3440626090 R15: 00007ffc05782498
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/03 10:59 upstream 075b74841bd0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root BUG: soft lockup in mrp_join_timer
* Struck through repros no longer work on HEAD.