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INFO: rcu detected stall in ipv6_list_rcv

Status: upstream: reported on 2026/06/04 21:34
Reported-by: syzbot+1a8ee08789c587229c99@syzkaller.appspotmail.com
First crash: 1d23h, last: 1d23h
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in ipv6_list_rcv (2) 1 1 62d 62d 0/3 upstream: reported on 2026/04/05 06:20
upstream INFO: rcu detected stall in ipv6_list_rcv (3) net 1 6 533d 738d 0/29 auto-obsoleted due to no activity on 2025/03/20 19:56
linux-6.1 INFO: rcu detected stall in ipv6_list_rcv 1 2 455d 458d 0/3 auto-obsoleted due to no activity on 2025/06/16 07:00
upstream INFO: rcu detected stall in ipv6_list_rcv (2) net 1 1 1704d 1704d 0/29 auto-closed as invalid on 2021/12/05 01:49
upstream INFO: rcu detected stall in ipv6_list_rcv trace 1 2 2005d 2006d 0/29 auto-closed as invalid on 2021/03/09 05:51

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10496 ticks this GP) idle=8e3c/1/0x4000000000000000 softirq=11924/11925 fqs=3
rcu: 	(t=10500 jiffies g=9941 q=754 ncpus=2)
rcu: rcu_preempt kthread starved for 10492 jiffies! g9941 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:26888 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5998 Comm: syz.2.51 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline]
RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline]
RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:196
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 db 55 24 03 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0018:ffffc900001efe70 EFLAGS: 00000046
RAX: 00000000000000fd RBX: ffff8880b8f282c0 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 00000000000000fd RDI: 0000000000000838
RBP: 0000000000000000 R08: ffffffff8e8b666f R09: 1ffffffff1d16ccd
R10: dffffc0000000000 R11: fffffbfff1d16cce R12: dffffc0000000000
R13: 0000000010005a98 R14: 00000000000000fd R15: 0000000000000020
FS:  00007f88abd236c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000070d000 CR3: 00000000756e4000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 apic_write arch/x86/include/asm/apic.h:404 [inline]
 lapic_next_event+0x11/0x20 arch/x86/kernel/apic/apic.c:448
 clockevents_program_event+0x1c0/0x310 kernel/time/clockevents.c:334
 hrtimer_interrupt+0x5a1/0x9c0 kernel/time/hrtimer.c:1893
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x96/0x120 kernel/kcov.c:350
Code: 41 54 53 48 8b 54 24 20 65 4c 8b 05 74 85 7c 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 62 85 7c 7e <41> 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 41 83 b8 1c
RSP: 0018:ffffc900001f00d0 EFLAGS: 00000246
RAX: 0000000000000003 RBX: ffffffff8faeb89b RCX: 0000000000000003
RDX: ffffffff813b4606 RSI: ffffffff8cfa0870 RDI: 0000000000000002
RBP: ffffc900001f0218 R08: ffff888027850000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000102 R12: ffffc900001f01c8
R13: dffffc0000000000 R14: 0000000000000002 R15: ffffffff8faeb89a
 unwind_next_frame+0xe46/0x2970 arch/x86/kernel/unwind_orc.c:581
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x270 mm/slub.c:3852
 kfree_skb include/linux/skbuff.h:1264 [inline]
 ip6_mc_input+0xaa0/0xcb0 net/ipv6/ip6_input.c:589
 dst_input include/net/dst.h:477 [inline]
 ip6_sublist_rcv_finish net/ipv6/ip6_input.c:88 [inline]
 ip6_list_rcv_finish net/ipv6/ip6_input.c:146 [inline]
 ip6_sublist_rcv+0xe1c/0x1150 net/ipv6/ip6_input.c:320
 ipv6_list_rcv+0x3f5/0x450 net/ipv6/ip6_input.c:355
 __netif_receive_skb_list_ptype net/core/dev.c:5689 [inline]
 __netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5737
 __netif_receive_skb_list net/core/dev.c:5789 [inline]
 netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5880
 netif_receive_skb_list+0x54/0x3f0 net/core/dev.c:5932
 ieee80211_rx_napi+0x35b/0x3d0 net/mac80211/rx.c:5464
 ieee80211_rx include/net/mac80211.h:4971 [inline]
 ieee80211_handle_queued_frames+0x106/0x1a0 net/mac80211/main.c:319
 tasklet_action_common+0x302/0x4d0 kernel/softirq.c:809
 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:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:127 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:178 [inline]
RIP: 0010:kasan_check_range+0x89/0x290 mm/kasan/generic.c:187
Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 3d 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 8d 01 00 00 49 ff c3 48 ff c3 75 ee e9 1d 01 00 00 44 89 dd
RSP: 0018:ffffc90004ea7868 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff8a905736
RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90004ea7a50
RBP: 0000000000000000 R08: ffffc90004ea7a5f R09: 1ffff920009d4f4b
R10: dffffc0000000000 R11: fffff520009d4f4b R12: 0000000000000002
R13: ffffc90004ea7a50 R14: fffff520009d4f4c R15: 1ffff920009d4f4a
 __asan_memset+0x22/0x40 mm/kasan/shadow.c:84
 __schedule+0xc6/0x45a0 kernel/sched/core.c:6583
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __mutex_lock_common kernel/locking/mutex.c:613 [inline]
 __mutex_lock+0x333/0xcc0 kernel/locking/mutex.c:747
 __do_sys_perf_event_open kernel/events/core.c:12967 [inline]
 __se_sys_perf_event_open+0x18b4/0x1c50 kernel/events/core.c:12609
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f88aad9ce59
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:00007f88abd23028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f88ab015fa0 RCX: 00007f88aad9ce59
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 00002000000012c0
RBP: 00007f88aae32d6f R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f88ab016038 R14: 00007f88ab015fa0 R15: 00007fff687c6018
 </TASK>
CPU: 0 PID: 5992 Comm: syz.0.49 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 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 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90000006c20 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 73f828966d010f00
RDX: 0000000000000000 RSI: ffffffff8acadd60 RDI: ffffffff8b1c9c20
RBP: ffffc90000006d28 R08: dffffc0000000000 R09: 1ffffffff2239aa0
R10: dffffc0000000000 R11: fffffbfff2239aa1 R12: 1ffff92000000d90
R13: ffffffff8d132160 R14: 0000000000000246 R15: dffffc0000000000
FS:  00007effc97f66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 000000005d3a7000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 __skb_flow_dissect+0x213/0x6dd0 net/core/flow_dissector.c:1096
 skb_flow_dissect_flow_keys include/linux/skbuff.h:1544 [inline]
 ___skb_get_hash net/core/flow_dissector.c:1798 [inline]
 __skb_get_hash+0xf3/0x2e0 net/core/flow_dissector.c:1863
 skb_get_hash include/linux/skbuff.h:1586 [inline]
 skb_tx_hash net/core/dev.c:3312 [inline]
 netdev_pick_tx+0x3bd/0xc20 net/core/dev.c:4295
 netdev_core_pick_tx+0x132/0x340 net/core/dev.c:4328
 __dev_queue_xmit+0x9e0/0x3660 net/core/dev.c:4410
 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:preempt_schedule_irq+0xba/0x150 kernel/sched/core.c:7010
Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 6f bf 01 00 00 00 e8 a1 ea cb f6 e8 4c fd fc f6 fb bf 01 00 00 00 <e8> f1 b4 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc90004df7a60 EFLAGS: 00000286
RAX: 73f828966d010f00 RBX: 0000000000000000 RCX: 73f828966d010f00
RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: 0000000000000001
RBP: ffffc90004df7b00 R08: ffffffff911cd53f R09: 1ffffffff2239aa7
R10: dffffc0000000000 R11: fffffbfff2239aa8 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920009bef4c
 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:perf_trace_init+0xa2/0x2d0 kernel/trace/trace_event_perf.c:223
Code: c0 83 18 8d 0f 84 75 01 00 00 4c 89 24 24 4c 8d 63 30 4c 89 e0 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 17 01 00 00 4d 63 24 24 <4c> 89 ff 4c 89 e6 e8 c3 e2 f7 ff 4d 39 e7 0f 85 a9 00 00 00 4c 8d
RSP: 0018:ffffc90004df7bc0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8d575c20 RCX: 0000000000080000
RDX: ffffc9000ce09000 RSI: 000000000000122f RDI: 0000000000001230
RBP: 0000000000000002 R08: ffffffff8e8b666f R09: 1ffffffff1d16ccd
R10: dffffc0000000000 R11: fffffbfff1d16cce R12: 00000000000006aa
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000028
 perf_tp_event_init+0x8d/0x110 kernel/events/core.c:10236
 perf_try_init_event+0x12b/0x3c0 kernel/events/core.c:11860
 perf_init_event kernel/events/core.c:11930 [inline]
 perf_event_alloc+0xfa4/0x21b0 kernel/events/core.c:12211
 __do_sys_perf_event_open kernel/events/core.c:12718 [inline]
 __se_sys_perf_event_open+0x740/0x1c50 kernel/events/core.c:12609
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7effcb59ce59
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:00007effc97f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007effcb815fa0 RCX: 00007effcb59ce59
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000500
RBP: 00007effcb632d6f R08: 0000000000000008 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007effcb816038 R14: 00007effcb815fa0 R15: 00007ffc4a47ccb8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/04 21:33 linux-6.6.y 924b4a879cbb 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in ipv6_list_rcv
* Struck through repros no longer work on HEAD.