INFO: rcu detected stall in mrp_join_timer (3)

Status: upstream: reported on 2026/05/01 08:15
Reported-by: syzbot+cb6d0aaf7ecff4d68410@syzkaller.appspotmail.com
First crash: 101d, last: 41d
▶ ▼ 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 672d 801d 0/29 auto-obsoleted due to no activity on 2025/01/05 17:43
linux-6.1 INFO: rcu detected stall in mrp_join_timer 1 1 731d 731d 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 260d 260d 0/3 auto-obsoleted due to no activity on 2026/03/04 01:39
linux-4.14 INFO: rcu detected stall in mrp_join_timer 1 7 2244d 2409d 0/1 auto-closed as invalid on 2020/10/17 01:22
upstream INFO: rcu detected stall in mrp_join_timer net 1 1 2406d 2406d 0/29 closed as invalid on 2020/01/09 08:13
linux-4.19 INFO: rcu detected stall in mrp_join_timer 1 28 2094d 2406d 0/1 auto-closed as invalid on 2021/03/15 12:15
upstream INFO: rcu detected stall in mrp_join_timer (3) net 1 1 965d 965d 0/29 closed as invalid on 2024/02/01 10:31
upstream INFO: rcu detected stall in mrp_join_timer (2) net 1 57 1618d 2367d 0/29 auto-closed as invalid on 2022/07/04 18:27
upstream BUG: soft lockup in mrp_join_timer (4) net 1 1 377d 377d 0/29 closed as invalid on 2025/09/01 08:24
linux-4.14 BUG: soft lockup in mrp_join_timer 1 1 1967d 1967d 0/1 auto-closed as invalid on 2021/07/20 15:25
upstream BUG: soft lockup in mrp_join_timer (2) net 1 1 1043d 1043d 0/29 closed as invalid on 2023/11/01 18:32
linux-4.19 BUG: soft lockup in mrp_join_timer (2) 1 58 1265d 1942d 0/1 upstream: reported on 2021/04/16 18:29
upstream BUG: soft lockup in mrp_join_timer (3) net 1 2 462d 467d 0/29 closed as invalid on 2025/06/11 12:25

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10496 ticks this GP) idle=eff4/1/0x4000000000000000 softirq=12255/12256 fqs=8
	(t=10500 jiffies g=10941 q=2973 ncpus=2)
rcu: rcu_preempt kthread starved for 10479 jiffies! g10941 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:5245 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5149 Comm: syz.4.271 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:debug_objects_fill_pool+0x8e/0x700 lib/debugobjects.c:608
Code: f9 f8 f8 f8 4b 89 04 2e 4b 89 4c 2e 08 48 b8 f8 f8 f8 f8 f3 f3 f3 f3 4b 89 44 2e 10 8b 05 fa 3a 07 09 3b 05 b8 f4 0b 0a 7c 49 <48> c7 44 24 40 0e 36 e0 45 4b c7 04 2e 00 00 00 00 4b c7 44 2e 08
RSP: 0000:ffffc90000007520 EFLAGS: 00000002
RAX: 0000000000000135 RBX: ffff88807c72f960 RCX: f8f8f8f8f8f8f8f8
RDX: 0000000000010100 RSI: ffffffff8a8e07a0 RDI: ffff88807c72f960
RBP: ffffc90000007668 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000ec0 R12: dffffc0000000000
R13: dffffc0000000000 R14: 1ffff92000000eac R15: 0000000000000000
FS:  00007ff3b3be66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3021dff8 CR3: 000000003a9d2000 CR4: 00000000003506f0
DR0: 0000000000000003 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 debug_object_activate+0x32/0x4f0 lib/debugobjects.c:694
 debug_hrtimer_activate kernel/time/hrtimer.c:448 [inline]
 debug_activate kernel/time/hrtimer.c:502 [inline]
 enqueue_hrtimer+0x37/0x410 kernel/time/hrtimer.c:1097
 __run_hrtimer kernel/time/hrtimer.c:1768 [inline]
 __hrtimer_run_queues+0x63e/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [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> ef cb 23 f7 65 8b 05 f0 7c cd 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0000:ffffc90000007a80 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: 916af816a9e3ee00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: ffffc90000007b00 R08: ffffffff90af2327 R09: 1ffffffff215e464
R10: dffffc0000000000 R11: fffffbfff215e465 R12: dffffc0000000000
R13: ffff8880584b54f0 R14: ffff8880584b5508 R15: 1ffff92000000f50
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 skb_dequeue+0x120/0x150 net/core/skbuff.c:3424
 mrp_queue_xmit net/802/mrp.c:363 [inline]
 mrp_join_timer+0x8d/0x170 net/802/mrp.c:608
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:raw_spin_rq_unlock_irq+0x13/0x90 kernel/sched/sched.h:1375
Code: 38 c1 7c d2 e8 ae 74 78 00 eb cb 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 41 57 41 56 53 66 90 e8 24 1d da 08 e8 9f b3 2d 00 fb 5b <41> 5e 41 5f c3 49 be 00 00 00 00 00 fc ff df 49 89 ff 48 8d 9f 58
RSP: 0000:ffffc900031f7d28 EFLAGS: 00000282
RAX: 916af816a9e3ee00 RBX: ffff8880b8e3add4 RCX: 916af816a9e3ee00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: ffffc900031f7ee0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: ffff888019263c00
R13: dffffc0000000000 R14: ffff888019263c00 R15: ffff8880b8e3ad00
 __schedule+0x130a/0x4030 kernel/sched/core.c:6568
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 exit_to_user_mode_loop+0x47/0x110 kernel/entry/common.c:165
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7ff3b2d9ce59
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:00007ff3b3be60e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007ff3b3015fa8 RCX: 00007ff3b2d9ce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff3b3015fa8
RBP: 00007ff3b3015fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff3b3016038 R14: 00007fffa1bfa0e0 R15: 00007fffa1bfa1c8
 </TASK>
CPU: 1 PID: 5146 Comm: syz.0.280 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5666
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0000:ffffc900001dfda0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ea16cbac97d6c300
RDX: 0000000000000000 RSI: ffffffff8a8c2920 RDI: ffffffff8adee1a0
RBP: ffffc900001dfec0 R08: dffffc0000000000 R09: 1ffffffff215e448
R10: dffffc0000000000 R11: fffffbfff215e449 R12: 0000000000000001
R13: 1ffff9200003bfc0 R14: 0000000000000246 R15: dffffc0000000000
FS:  00007fa9e24476c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9e2426d58 CR3: 000000007dc9c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 page_ext_get+0x3a/0x2a0 mm/page_ext.c:157
 __set_page_owner+0x24/0x60 mm/page_owner.c:192
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
 prep_new_page mm/page_alloc.c:2567 [inline]
 get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
 alloc_slab_page+0x5d/0x180 mm/slub.c:1799
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:1997
 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x111/0x2f0 mm/slub.c:3383
 skb_clone+0x1e7/0x370 net/core/skbuff.c:1660
 dev_queue_xmit_nit+0x23b/0xba0 net/core/dev.c:2334
 xmit_one net/core/dev.c:3691 [inline]
 dev_hard_start_xmit+0x158/0x8b0 net/core/dev.c:3711
 __dev_queue_xmit+0x1b4b/0x3810 net/core/dev.c:4375
 dev_queue_xmit include/linux/netdevice.h:3051 [inline]
 neigh_hh_output include/net/neighbour.h:529 [inline]
 neigh_output include/net/neighbour.h:543 [inline]
 ip6_finish_output2+0xd8f/0x15c0 net/ipv6/ip6_output.c:138
 dst_output include/net/dst.h:453 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ndisc_send_skb+0xc04/0x1520 net/ipv6/ndisc.c:513
 addrconf_rs_timer+0x367/0x640 net/ipv6/addrconf.c:3979
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:finish_task_switch+0x267/0x8e0 kernel/sched/core.c:5124
Code: d1 08 85 c0 0f 84 38 01 00 00 48 85 db 0f 85 57 01 00 00 0f 1f 44 00 00 4c 89 e7 e8 33 6f db 08 e8 ae 05 2f 00 fb 4c 8b 65 b8 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0000:ffffc90003157ba0 EFLAGS: 00000286
RAX: ea16cbac97d6c300 RBX: 0000000000000000 RCX: ea16cbac97d6c300
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: ffffc90003157bf0 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: ffff88807c649e00
R13: 1ffff110171e76fa R14: dffffc0000000000 R15: ffff8880b8f3b7d0
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x1087/0x4030 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 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:exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
Code: fb eb 1d e8 f2 00 bc 08 65 48 8b 05 5a 81 93 7e 4c 8b 30 41 f7 c6 0e 30 02 00 0f 84 c4 00 00 00 e8 d5 99 19 00 fb 41 f6 c6 08 <74> 05 e8 b9 84 c4 08 41 f7 c6 00 10 00 00 74 08 48 89 df e8 18 d5
RSP: 0000:ffffc90003157f10 EFLAGS: 00000202
RAX: ea16cbac97d6c300 RBX: ffffc90003157f58 RCX: ea16cbac97d6c300
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: 0000000000000000 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000008 R15: ffff88807c649e00
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7fa9e1462e7f
Code: 4c 89 e7 31 c0 e8 61 e6 fe ff 4c 8b 74 24 08 48 89 ef 31 c0 49 8b 74 de 30 48 83 c3 01 e8 49 e6 fe ff 41 39 5e 2c 7f d3 31 c0 <48> 8d 3d f6 cb 1e 00 e8 35 e6 fe ff 48 8b 44 24 08 44 8b 60 78 c6
RSP: 002b:00007fa9e2447050 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fa9e164af98
RDX: 000000000000f5d1 RSI: 0000000000000000 RDI: 00007fa9e1632e6f
RBP: 00007fa9e1632e6f R08: 0000000000000077 R09: 0001651614a46d40
R10: 0000003fc8f24a50 R11: 00000000000058ae R12: 00007fa9e1633838
R13: 00007fa9e1816038 R14: 00007fa9e1815fa0 R15: 00007ffcd357bd38
 </TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 5146 Comm: syz.0.280 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:strcpy+0x34/0xa0 lib/string.c:88
Code: f8 48 bb 00 00 00 00 00 fc ff df 45 31 f6 4a 8d 3c 36 48 89 f9 48 c1 e9 03 0f b6 0c 19 84 c9 75 26 42 0f b6 2c 36 4a 8d 3c 30 <48> 89 f9 48 c1 e9 03 0f b6 0c 19 84 c9 75 2a 42 88 2c 30 49 ff c6
RSP: 0000:ffffc900001dffd0 EFLAGS: 00000046
RAX: ffffe8ffffdc2018 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000150018 RSI: ffffffff8a8e0da0 RDI: ffffe8ffffdc2019
RBP: 000000000000006b R08: 0000000000000002 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff1c401ee R12: ffffe8ffffdc2000
R13: 0000000000000034 R14: 0000000000000001 R15: dffffc0000000000
FS:  00007fa9e24476c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9e2426d58 CR3: 000000007dc9c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 strcpy include/linux/fortify-string.h:600 [inline]
 perf_trace_lock_acquire+0x2f6/0x3f0 include/trace/events/lock.h:40
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x452/0x4a0 kernel/locking/lockdep.c:5633
 seqcount_lockdep_reader_access+0xcd/0x1d0 include/linux/seqlock.h:102
 ktime_get+0x31/0x270 kernel/time/timekeeping.c:846
 hrtimer_forward_now include/linux/hrtimer.h:509 [inline]
 perf_swevent_hrtimer+0x4f8/0x630 kernel/events/core.c:10972
 __run_hrtimer kernel/time/hrtimer.c:1751 [inline]
 __hrtimer_run_queues+0x4e7/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 e2 82 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0000:ffffc900001e08e0 EFLAGS: 00000206
RAX: ea16cbac97d6c300 RBX: 1ffff9200003c124 RCX: ea16cbac97d6c300
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: ffffc900001e09d0 R08: ffffffff90af2337 R09: 1ffffffff215e466
R10: dffffc0000000000 R11: fffffbfff215e467 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3bb00 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ndisc_alloc_skb+0x357/0x450 net/ipv6/ndisc.c:438
 ndisc_send_rs+0x279/0x690 net/ipv6/ndisc.c:707
 addrconf_rs_timer+0x367/0x640 net/ipv6/addrconf.c:3979
 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:finish_task_switch+0x267/0x8e0 kernel/sched/core.c:5124
Code: d1 08 85 c0 0f 84 38 01 00 00 48 85 db 0f 85 57 01 00 00 0f 1f 44 00 00 4c 89 e7 e8 33 6f db 08 e8 ae 05 2f 00 fb 4c 8b 65 b8 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0000:ffffc90003157ba0 EFLAGS: 00000286
RAX: ea16cbac97d6c300 RBX: 0000000000000000 RCX: ea16cbac97d6c300
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: ffffc90003157bf0 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: ffff88807c649e00
R13: 1ffff110171e76fa R14: dffffc0000000000 R15: ffff8880b8f3b7d0
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x1087/0x4030 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 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:exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
Code: fb eb 1d e8 f2 00 bc 08 65 48 8b 05 5a 81 93 7e 4c 8b 30 41 f7 c6 0e 30 02 00 0f 84 c4 00 00 00 e8 d5 99 19 00 fb 41 f6 c6 08 <74> 05 e8 b9 84 c4 08 41 f7 c6 00 10 00 00 74 08 48 89 df e8 18 d5
RSP: 0000:ffffc90003157f10 EFLAGS: 00000202
RAX: ea16cbac97d6c300 RBX: ffffc90003157f58 RCX: ea16cbac97d6c300
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: 0000000000000000 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000008 R15: ffff88807c649e00
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7fa9e1462e7f
Code: 4c 89 e7 31 c0 e8 61 e6 fe ff 4c 8b 74 24 08 48 89 ef 31 c0 49 8b 74 de 30 48 83 c3 01 e8 49 e6 fe ff 41 39 5e 2c 7f d3 31 c0 <48> 8d 3d f6 cb 1e 00 e8 35 e6 fe ff 48 8b 44 24 08 44 8b 60 78 c6
RSP: 002b:00007fa9e2447050 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fa9e164af98
RDX: 000000000000f5d1 RSI: 0000000000000000 RDI: 00007fa9e1632e6f
RBP: 00007fa9e1632e6f R08: 0000000000000077 R09: 0001651614a46d40
R10: 0000003fc8f24a50 R11: 00000000000058ae R12: 00007fa9e1633838
R13: 00007fa9e1816038 R14: 00007fa9e1815fa0 R15: 00007ffcd357bd38
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/30 06:19 linux-6.1.y fdb6fcb41cc7 fff8d0a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in mrp_join_timer
2026/06/30 04:47 linux-6.1.y fdb6fcb41cc7 fff8d0a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in mrp_join_timer
2026/05/01 08:14 linux-6.1.y 4931e0e1673d 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in mrp_join_timer
* Struck through repros no longer work on HEAD.