INFO: rcu detected stall in mld_dad_work (4)

Status: closed as invalid on 2026/04/30 15:35
Subsystems: net
[Documentation on labels]
First crash: 257d, last: 220d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in mld_dad_work (2) net 1 1 926d 926d 0/29 auto-obsoleted due to no activity on 2024/04/28 18:46
upstream INFO: rcu detected stall in mld_dad_work (3) mm 1 2 357d 368d 0/29 auto-obsoleted due to no activity on 2025/11/18 11:46
upstream INFO: rcu detected stall in mld_dad_work net 1 syz, C error 3 1112d 1229d 0/29 closed as invalid on 2023/09/22 04:28
android-5-15 BUG: soft lockup in mld_dad_work origin:lts 1 syz 1 699d 699d 0/2 auto-obsoleted due to no activity on 2024/12/11 14:40
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2026/02/21 13:09 33m retest repro linux-next report log
2026/02/21 13:08 21m retest repro linux-next report log
2025/12/13 09:40 21m retest repro linux-next report log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4482/1:b..l P5946/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=11641, q=415 ncpus=2)
task:kworker/1:4     state:R  running task     stack:23128 pid:5946  tgid:5946  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: mld mld_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6864
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 74 17 23 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90003397158 EFLAGS: 00000206
RAX: 6de5677246b83900 RBX: 0000000000000000 RCX: 6de5677246b83900
RDX: 00000000222db22a RSI: ffffffff8dc7e873 RDI: ffffffff8be1e760
RBP: ffffffff81747f85 R08: ffffffff81747f85 R09: ffffffff8e3419e0
R10: ffffc90003397318 R11: ffffffff81ade230 R12: 0000000000000002
R13: ffffffff8e3419e0 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4948 [inline]
 slab_alloc_node mm/slub.c:5258 [inline]
 kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5310
 __alloc_skb+0x255/0x430 net/core/skbuff.c:679
 alloc_skb include/linux/skbuff.h:1383 [inline]
 mld_newpack+0x13c/0xc40 net/ipv6/mcast.c:1775
 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886
 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025
 mld_send_initial_cr+0x288/0x550 net/ipv6/mcast.c:2268
 mld_dad_work+0x46/0x490 net/ipv6/mcast.c:2294
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
task:kworker/u8:12   state:R  running task     stack:23392 pid:4482  tgid:4482  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound cfg80211_wiphy_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6864
 preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7141
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x4b/0x3b0 kernel/locking/lockdep.c:5879
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:897 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5652 [inline]
 __kmalloc_noprof+0x41d/0x800 mm/slub.c:5664
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 cfg80211_inform_single_bss_data+0x91e/0x1ad0 net/wireless/scan.c:2345
 cfg80211_inform_bss_data+0x203/0x3b40 net/wireless/scan.c:3228
 cfg80211_inform_bss_frame_data+0x3c7/0x710 net/wireless/scan.c:3319
 ieee80211_bss_info_update+0x749/0x9e0 net/mac80211/scan.c:230
 ieee80211_rx_bss_info net/mac80211/ibss.c:1094 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1575 [inline]
 ieee80211_ibss_rx_queued_mgmt+0xa5d/0x2af0 net/mac80211/ibss.c:1602
 ieee80211_iface_process_skb net/mac80211/iface.c:1736 [inline]
 ieee80211_iface_work+0x85f/0x12d0 net/mac80211/iface.c:1790
 cfg80211_wiphy_work+0x2ab/0x450 net/wireless/core.c:438
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: rcu_preempt kthread starved for 10592 jiffies! g11641 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:27128 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6864
 __schedule_loop kernel/sched/core.c:6946 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6961
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 6047 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ba 58 39 f6 48 89 df e8 f2 cf 39 f6 e8 bd 39 64 f6 fb bf 01 00 00 00 <e8> f2 bf 2b f6 65 8b 05 ab 40 5c 07 85 c0 74 07 5b e9 51 4d 00 00
RSP: 0018:ffffc90002ff7c60 EFLAGS: 00000286
RAX: df4d5508ddae4800 RBX: ffff88802cf0d340 RCX: df4d5508ddae4800
RDX: 0000000000000000 RSI: ffffffff8da95064 RDI: 0000000000000001
RBP: 0000000000000011 R08: ffffffff8fc2d477 R09: 1ffffffff1f85a8e
R10: dffffc0000000000 R11: fffffbfff1f85a8f R12: 1ffff110059e1abb
R13: 0000000000000000 R14: 0000000004000000 R15: ffff88802cf0d5d8
FS:  000055558aeca500(0000) GS:ffff888125b03000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffce0d96080 CR3: 0000000072af8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x11a7/0x1340 kernel/signal.c:3037
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7118d8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffce0d96128 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f7118fe7da0 RCX: 00007f7118d8f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f7118fe7da0 R08: 0000000000000000 R09: 00000007e0d9641f
R10: 00007f7118fe7cb0 R11: 0000000000000246 R12: 0000000000016b90
R13: 00007f7118fe6090 R14: ffffffffffffffff R15: 00007ffce0d96240
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/29 03:00 linux-next 7d31f578f323 d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: rcu detected stall in mld_dad_work
2026/01/04 08:36 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in mld_dad_work
* Struck through repros no longer work on HEAD.