rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6173/1:b.el P6178/1:b..l
rcu: (detected by 1, t=11406 jiffies, g=13905, q=975 ncpus=2)
task:syz-executor state:R running task stack:28488 pid:6178 tgid:6177 ppid:6176 task_flags:0x400040 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7145
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7169
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
wp_page_copy mm/memory.c:3653 [inline]
do_wp_page+0x1d1d/0x5800 mm/memory.c:4013
handle_pte_fault mm/memory.c:6068 [inline]
__handle_mm_fault+0x1033/0x5440 mm/memory.c:6195
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364
do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f9887548715
RSP: 002b:00007f98873fe910 EFLAGS: 00010293
RAX: 0000000000000008 RBX: 00007f98882f7d60 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00007f988764f8dd RDI: 00007f98882f7d60
RBP: 00007f98873fea30 R08: 0000000000000000 R09: 0000000000000005
R10: 00000000ffffffff R11: 0000000000000293 R12: 00007f988764f5a0
R13: 0000000000000006 R14: 00007f9887797460 R15: 00007ffcaab896c8
task:udevd state:R running task stack:27688 pid:6173 tgid:6173 ppid:5234 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7145
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7169
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
wp_page_copy mm/memory.c:3653 [inline]
do_wp_page+0x1d1d/0x5800 mm/memory.c:4013
handle_pte_fault mm/memory.c:6068 [inline]
__handle_mm_fault+0x1033/0x5440 mm/memory.c:6195
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364
do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7efe71c9ea9a
RSP: 002b:00007fffdf3664e0 EFLAGS: 00010202
RAX: 000055bf409660b0 RBX: 000055bf40965a30 RCX: 0000000000000000
RDX: 000055bf40971430 RSI: 000055bf4096df60 RDI: 000055bf4096b4e0
RBP: 000055bf4096b4e0 R08: 000055bf4096df70 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000297 R12: 000055bf1cc57588
R13: 00007fffdf366590 R14: 0000000000000000 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 11112 jiffies! g13905 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:26632 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
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+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5864 Comm: kworker/0:3 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5806 [inline]
RIP: 0010:preempt_count_add+0x74/0x1a0 kernel/sched/core.c:5832
Code: c1 e8 03 42 0f b6 04 38 84 c0 0f 85 ec 00 00 00 83 3d ff d6 1b 18 00 75 11 65 8b 05 06 84 10 11 0f b6 c0 3d f5 00 00 00 73 5e <65> 8b 05 f5 83 10 11 25 ff ff ff 7f 39 f8 75 43 48 8b 5c 24 18 48
RSP: 0018:ffffc90000007c80 EFLAGS: 00000093
RAX: 0000000000000003 RBX: ffff8880b8627a80 RCX: ffffffff99abd303
RDX: 0000000000010000 RSI: ffffffff8be337e0 RDI: 0000000000000001
RBP: ffffc90000007d30 R08: ffffffff8fa38e37 R09: 1ffffffff1f471c6
R10: dffffc0000000000 R11: fffffbfff1f471c7 R12: ffff88807ae50340
R13: dffffc0000000000 R14: 1ffff92000000f94 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888125c18000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f1b94f9660 CR3: 000000000df36000 CR4: 00000000003526f0
Call Trace:
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:118 [inline]
_raw_spin_lock_irq+0x87/0xf0 kernel/locking/spinlock.c:170
__run_hrtimer kernel/time/hrtimer.c:1765 [inline]
__hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 6b f7 4a f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 53 9f 13 f6 65 8b 05 0c 22 24 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc9000408f900 EFLAGS: 00000206
RAX: 65280b2cfd58d700 RBX: 0000000000000282 RCX: 65280b2cfd58d700
RDX: 0000000000000002 RSI: ffffffff8d9b8072 RDI: 0000000000000001
RBP: ffffc9000408f988 R08: ffffffff8fa38e37 R09: 1ffffffff1f471c6
R10: dffffc0000000000 R11: fffffbfff1f471c7 R12: dffffc0000000000
R13: ffff88801b7b4010 R14: ffff8880b8633cb0 R15: 1ffff92000811f20
krc_this_cpu_unlock mm/slab_common.c:1451 [inline]
kvfree_call_rcu+0x374/0x410 mm/slab_common.c:1994
neigh_periodic_work+0xb4f/0xe50 net/core/neighbour.c:1031
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245