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INFO: rcu detected stall in addrconf_rs_timer

Status: upstream: reported C repro on 2025/11/29 19:55
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+1c0f13d7bc65d06d5fc9@syzkaller.appspotmail.com
First crash: 155d, last: 13d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/04/20 linux-6.6.y (ToT) 9760bf04666d C [report] INFO: rcu detected stall in smp_call_function
2026/04/20 upstream (ToT) c1f49dea2b8f C Didn't crash
▶ ▼ Similar bugs (31)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in addrconf_rs_timer (2) net 1 362 2405d 2427d 13/29 fixed on 2019/10/21 12:31
linux-4.14 INFO: rcu detected stall in addrconf_rs_timer 1 C error 220 2068d 2431d 0/1 upstream: reported C repro on 2019/09/06 14:33
upstream INFO: rcu detected stall in addrconf_rs_timer net 1 38 2691d 2787d 0/29 closed as dup on 2019/01/02 16:33
linux-4.19 INFO: rcu detected stall in addrconf_rs_timer 1 45 2419d 2431d 0/1 auto-closed as invalid on 2019/12/17 18:46
linux-4.19 BUG: soft lockup in addrconf_rs_timer 1 syz error 24 1189d 1871d 0/1 upstream: reported syz repro on 2021/03/19 06:05
linux-5.15 BUG: soft lockup in addrconf_rs_timer 1 C error 36 1054d 1067d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:06
upstream INFO: rcu detected stall in addrconf_rs_timer (3) net 1 C inconclusive done 81 2327d 2323d 15/29 fixed on 2020/02/18 14:31
linux-4.19 INFO: rcu detected stall in addrconf_rs_timer (2) 1 5 2069d 2143d 0/1 auto-closed as invalid on 2020/12/31 12:17
upstream INFO: rcu detected stall in addrconf_rs_timer (5) kvm 1 4 1469d 1469d 0/29 auto-closed as invalid on 2022/06/24 22:41
upstream INFO: rcu detected stall in addrconf_rs_timer (4) net 1 C error error 121 1645d 2099d 0/29 closed as invalid on 2022/02/08 10:39
linux-6.1 INFO: rcu detected stall in addrconf_rs_timer origin:lts-only 1 C done 98 53d 709d 0/3 upstream: reported C repro on 2024/05/24 18:08
linux-5.15 INFO: rcu detected stall in addrconf_rs_timer origin:lts-only 1 C error 102 2h28m 875d 0/3 upstream: reported C repro on 2023/12/10 10:27
upstream INFO: rcu detected stall in addrconf_rs_timer (6) virt mm netfilter 1 syz error error 701 19d 701d 0/29 upstream: reported syz repro on 2024/06/01 13:51
upstream BUG: soft lockup in addrconf_rs_timer (3) net 1 syz 8 949d 1013d 0/29 auto-obsoleted due to no activity on 2024/01/05 16:48
upstream BUG: soft lockup in addrconf_rs_timer (4) net 1 1 844d 844d 0/29 closed as invalid on 2024/03/12 13:17
android-6-1 BUG: soft lockup in addrconf_rs_timer 1 1 917d 917d 0/2 auto-obsoleted due to no activity on 2024/01/27 13:54
android-5-10 BUG: soft lockup in addrconf_rs_timer (2) 1 C 265 349d 680d 0/2 auto-obsoleted due to no activity on 2025/07/28 18:01
android-6-1 BUG: soft lockup in addrconf_rs_timer (5) 1 1 14d 14d 0/2 premoderation: reported on 2026/04/19 17:29
android-5-10 BUG: soft lockup in addrconf_rs_timer 1 2 1008d 1026d 0/2 auto-obsoleted due to no activity on 2023/10/29 01:38
linux-6.1 BUG: soft lockup in addrconf_rs_timer 1 C done 26 1055d 1067d 3/3 fixed on 2023/07/30 15:47
linux-4.14 BUG: soft lockup in addrconf_rs_timer 1 C error 133 1227d 2429d 0/1 upstream: reported C repro on 2019/09/08 14:09
android-5-10 BUG: soft lockup in addrconf_rs_timer (3) 1 1 89d 89d 0/2 premoderation: reported on 2026/02/04 01:38
android-5-15 BUG: soft lockup in addrconf_rs_timer (3) 1 1 13d 13d 0/2 premoderation: reported on 2026/04/20 17:07
android-5-15 BUG: soft lockup in addrconf_rs_timer (2) 1 syz 99 493d 736d 0/2 auto-obsoleted due to no activity on 2025/02/14 09:13
android-6-1 BUG: soft lockup in addrconf_rs_timer (3) 1 1 394d 394d 0/2 auto-obsoleted due to no activity on 2025/07/03 20:11
android-54 BUG: soft lockup in addrconf_rs_timer 1 190 669d 724d 0/2 auto-obsoleted due to no activity on 2024/08/22 17:20
android-6-1 BUG: soft lockup in addrconf_rs_timer (2) 1 syz 176 515d 720d 0/2 auto-obsoleted due to no activity on 2025/01/24 01:43
upstream BUG: soft lockup in addrconf_rs_timer (2) net 1 C 51 1047d 1068d 23/29 fixed on 2023/07/04 09:17
android-6-1 BUG: soft lockup in addrconf_rs_timer (4) 1 7 117d 265d 0/2 auto-obsoleted due to no activity on 2026/04/06 21:21
android-5-15 BUG: soft lockup in addrconf_rs_timer 1 1 1015d 1015d 0/2 auto-obsoleted due to no activity on 2023/10/21 14:14
upstream BUG: soft lockup in addrconf_rs_timer net 1 18 2233d 2429d 0/29 auto-closed as invalid on 2020/07/20 22:25
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2026/04/23 04:40 12m fix candidate upstream error job log
2026/03/23 04:41 1m fix candidate upstream error job log
2026/02/21 04:32 1m fix candidate upstream error job log
2026/01/21 13:20 1m fix candidate upstream error job log

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=d0dc/1/0x4000000000000000 softirq=11630/11633 fqs=3
rcu: 	(t=10500 jiffies g=9325 q=453 ncpus=2)
rcu: rcu_preempt kthread starved for 10493 jiffies! g9325 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:27656 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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: 5942 Comm: syz.3.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:lockdep_hardirqs_on+0xa3/0x150 kernel/locking/lockdep.c:4422
Code: 48 8b 83 b8 0a 00 00 48 3b 83 d0 0a 00 00 75 76 49 89 fe 48 c7 c7 e0 c9 ca 8a e8 58 15 00 00 65 c7 05 05 3b 7c 75 01 00 00 00 <4c> 89 b3 80 0a 00 00 8b 83 78 0a 00 00 ff c0 89 83 78 0a 00 00 89
RSP: 0000:ffffc900034772e0 EFLAGS: 00000086
RAX: 0000000000000000 RBX: ffff88807622bc00 RCX: c4aea09a9dffa200
RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8e60
RBP: 0000000000000000 R08: ffffffff911c5607 R09: 1ffffffff2238ac0
R10: dffffc0000000000 R11: fffffbfff2238ac1 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8aa0144a R15: 0000000000000000
FS:  000055557a70d500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d763fff CR3: 00000000312a0000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:unwind_next_frame+0x6ce/0x2970 arch/x86/kernel/unwind_orc.c:512
Code: 00 00 00 fc ff df 4d 8d 74 24 34 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 09 1d 00 00 41 c6 06 01 48 c7 c3 c0 4c c8 8a <4c> 8d 7b 04 4c 8d 73 05 4c 89 f8 48 c1 e8 03 48 89 44 24 48 42 0f
RSP: 0000:ffffc900034773b0 EFLAGS: 00000246
RAX: ffffffff813b3e39 RBX: ffffffff8f0da6de RCX: ffff88807622bc00
RDX: 0000000000000100 RSI: ffffffff8cfa07c0 RDI: 0000000000000002
RBP: ffffc90003477538 R08: ffff88807622bc00 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000100 R12: ffffc900034774e8
R13: dffffc0000000000 R14: 0000000000000002 R15: ffffffff8f0da6e3
 __unwind_start+0x66a/0x7e0 arch/x86/kernel/unwind_orc.c:760
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 ref_tracker_alloc+0x1b7/0x4c0 lib/ref_tracker.c:209
 __netdev_tracker_alloc include/linux/netdevice.h:4110 [inline]
 netdev_hold include/linux/netdevice.h:4139 [inline]
 dst_init+0xd9/0x480 net/core/dst.c:52
 dst_alloc+0x12e/0x170 net/core/dst.c:94
 ip6_dst_alloc net/ipv6/route.c:344 [inline]
 icmp6_dst_alloc+0x7b/0x400 net/ipv6/route.c:3317
 ndisc_send_skb+0x44e/0x14f0 net/ipv6/ndisc.c:493
 addrconf_rs_timer+0x2d5/0x630 net/ipv6/addrconf.c:4024
 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x542/0x800 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x56/0xc0 arch/x86/kernel/apic/apic.c:1088
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0033:0x7f2447f9c819
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:00007ffe4442e528 EFLAGS: 00000246
RAX: 0000000000000004 RBX: 00007f2448215fa0 RCX: 00007f2447f9c819
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000140
RBP: 00007f2448032c91 R08: 0000000000000002 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2448215fac R14: 00007f2448215fa0 R15: 00007f2448215fa0
 </TASK>
CPU: 1 PID: 5941 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:seqcount_lockdep_reader_access+0x19a/0x1d0 include/linux/seqlock.h:105
Code: 00 4d 85 e4 75 16 e8 95 c6 0f 00 eb 15 e8 8e c6 0f 00 e8 69 ef 0e 09 4d 85 e4 74 ea e8 7f c6 0f 00 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 43 c7 44 3e 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900001f0240 EFLAGS: 00000246
RAX: ffffffff81775b81 RBX: 0000000000000000 RCX: ffff888079d63c00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001f02f8 R08: ffffffff911c5607 R09: 1ffffffff2238ac0
R10: dffffc0000000000 R11: fffffbfff2238ac1 R12: 0000000000000200
R13: 000001fb6c80a799 R14: 1ffff9200003e048 R15: dffffc0000000000
FS:  0000555589bb9500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000138c CR3: 0000000075b37000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 ktime_get_with_offset+0x94/0x330 kernel/time/timekeeping.c:889
 ktime_get_real include/linux/timekeeping.h:79 [inline]
 netif_rx_internal+0x344/0x4e0 net/core/dev.c:5153
 __netif_rx+0x78/0xc0 net/core/dev.c:5196
 veth_forward_skb drivers/net/veth.c:325 [inline]
 veth_xmit+0x550/0x9f0 drivers/net/veth.c:378
 __netdev_start_xmit include/linux/netdevice.h:4943 [inline]
 netdev_start_xmit include/linux/netdevice.h:4957 [inline]
 xmit_one net/core/dev.c:3644 [inline]
 dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3660
 __dev_queue_xmit+0x19a3/0x3660 net/core/dev.c:4454
 dev_queue_xmit include/linux/netdevice.h:3113 [inline]
 neigh_hh_output include/net/neighbour.h:527 [inline]
 neigh_output include/net/neighbour.h:541 [inline]
 ip6_finish_output2+0xe06/0x1630 net/ipv6/ip6_output.c:141
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ndisc_send_skb+0xc26/0x14f0 net/ipv6/ndisc.c:513
 addrconf_rs_timer+0x2d5/0x630 net/ipv6/addrconf.c:4024
 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x542/0x800 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255
Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 00 89 32 09 e8 9b 29 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90003497938 EFLAGS: 00000282
RAX: c400e334d96b9200 RBX: 0000000000000000 RCX: c400e334d96b9200
RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8e60
RBP: ffffc90003497990 R08: ffffffff8e8b15ef R09: 1ffffffff1d162bd
R10: dffffc0000000000 R11: fffffbfff1d162be R12: ffff888079d63c00
R13: dffffc0000000000 R14: ffff888031b31e00 R15: ffff8880b8f3cac8
 context_switch kernel/sched/core.c:5384 [inline]
 __schedule+0x155b/0x45a0 kernel/sched/core.c:6700
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__sanitizer_cov_trace_switch+0x7/0x120 kernel/kcov.c:330
Code: ca 77 1e 49 ff c0 4c 89 02 48 c7 44 0a 08 07 00 00 00 48 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 c3 90 f3 0f 1e fa 48 8b 06 <48> 8b 4e 08 48 83 c1 f8 48 c1 c1 3d 48 83 f9 02 7f 1e 48 85 c9 74
RSP: 0018:ffffc90003497d38 EFLAGS: 00000293
RAX: 000000000000000d RBX: 1ffff92000692fb0 RCX: ffff888079d63c00
RDX: 0000000000000000 RSI: ffffffff8d155790 RDI: 0000000000000001
RBP: ffffc90003497e08 R08: 0000000000745af4 R09: 0000000000000004
R10: 000000000000000d R11: 0000000000000000 R12: 0000000000000001
R13: ffffc90003497da0 R14: 0000000000000000 R15: 0000000000000001
 do_futex+0xdb/0x3e0 kernel/futex/syscalls.c:129
 __do_sys_futex kernel/futex/syscalls.c:211 [inline]
 __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb77f39c819
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:00007fff71c44998 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb77f39c819
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fb77f615fac
RBP: 000000000000138c R08: 0000000000745af4 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb77f615fac R14: 00007fb77f615fa8 R15: 00007fb77f615fa0
 </TASK>

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/20 07:30 linux-6.6.y 9760bf04666d 303e2802 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2026/04/19 05:04 linux-6.6.y 9760bf04666d 303e2802 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2025/11/29 19:54 linux-6.6.y 1e89a1be4fe9 d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2026/04/17 12:23 linux-6.6.y 8cee53b8eaeb de0a551d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2026/03/31 20:43 linux-6.6.y c09fbcd31ae6 aeea1c72 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2026/03/29 22:29 linux-6.6.y c09fbcd31ae6 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2026/03/19 22:26 linux-6.6.y 4fc00fe35d46 bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2026/01/31 16:21 linux-6.6.y 2cf6f68313dc afc0c4d4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2025/12/30 07:50 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2025/11/29 20:47 linux-6.6.y 1e89a1be4fe9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in addrconf_rs_timer
2026/01/06 11:19 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf BUG: soft lockup in addrconf_rs_timer
* Struck through repros no longer work on HEAD.