rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4234/1:b..l
(detected by 0, t=10502 jiffies, g=6925, q=142)
task:kworker/1:5 state:R running task stack:24320 pid: 4234 ppid: 2 flags:0x00004000
Workqueue: mld mld_dad_work
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__local_bh_enable_ip+0x13b/0x1b0 kernel/softirq.c:408
rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline]
ip6_finish_output2+0x110b/0x1500 net/ipv6/ip6_output.c:131
dst_output include/net/dst.h:452 [inline]
NF_HOOK+0x15f/0x430 include/linux/netfilter.h:302
mld_sendpack+0x713/0xc30 net/ipv6/mcast.c:1825
mld_dad_work+0x41/0x270 net/ipv6/mcast.c:2267
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: rcu_preempt kthread starved for 10523 jiffies! g6925 f0x0 RCU_GP_DOING_FQS(6) ->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:28064 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5671
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc90000d47b58 EFLAGS: 00000206
RAX: 1a377e93c7f57400 RBX: ffff88813fea3b80 RCX: 1a377e93c7f57400
RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1824171
R10: fffffbfff1824171 R11: 1ffffffff1824170 R12: dffffc0000000000
R13: 0000000000000246 R14: ffffffff8c11c780 R15: 00000000ffffffff
lock_is_held include/linux/lockdep.h:287 [inline]
___might_sleep+0xa3/0x600 kernel/sched/core.c:9624
rcu_gp_fqs_loop+0xf5f/0x11b0 kernel/rcu/tree.c:1994
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
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: 4309 Comm: syz.4.5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4691 [inline]
RIP: 0010:__lock_acquire+0x661/0x7c60 kernel/locking/lockdep.c:4962
Code: 0f 85 2f 61 00 00 45 84 f6 0f 84 25 05 00 00 0f b6 1b 48 8b 44 24 58 42 0f b6 04 00 84 c0 0f 85 f3 61 00 00 41 f6 44 24 01 80 <0f> 85 04 05 00 00 84 db 41 0f b6 c6 0f b6 cb 0f 44 c8 89 8c 24 c8
RSP: 0018:ffffc90000dd08a0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff815c04ed
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffaa0c0
RBP: ffffc90000dd0af0 R08: dffffc0000000000 R09: fffffbfff1ff5419
R10: fffffbfff1ff5419 R11: 1ffffffff1ff5418 R12: ffff8880255c8b38
R13: ffff8880255c8000 R14: 0000000000000002 R15: ffff8880255c8b18
FS: 00007fd913e1f6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000002202e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
rcu_read_lock include/linux/rcupdate.h:740 [inline]
send_sigqueue+0xd1/0x620 kernel/signal.c:1973
posix_timer_event kernel/time/posix-timers.c:360 [inline]
posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be 2b b1 f7 48 89 df e8 86 00 b2 f7 e8 21 9a d2 f7 fb bf 01 00 00 00 56 22 a6 f7 65 8b 05 e7 1f 57 76 85 c0 74 02 5b c3 e8 f4 2a 55
RSP: 0018:ffffc9000332fbc0 EFLAGS: 00000282
RAX: 193fbc8552b12c00 RBX: ffff88805fffe5c0 RCX: 193fbc8552b12c00
RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: 0000000000000001
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100bfffcb9
R10: ffffed100bfffcb9 R11: 1ffff1100bfffcb8 R12: ffff88805fffe5c0
R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004
spin_unlock_irq include/linux/spinlock.h:414 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd915bb8747
Code: ff ff 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
RSP: 002b:00007fd913e1f0e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fd915e0efa8 RCX: 00007fd915bb8749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd915e0efa8
RBP: 00007fd915e0efa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd915e0f038 R14: 00007fffe976ac00 R15: 00007fffe976ace8