rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=1a2c/1/0x4000000000000000 softirq=47423/47423 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5622/1:b..l P9538/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=47353, q=786 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5621 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:__lock_acquire+0x5e5/0x1a40 kernel/locking/lockdep.c:5234
Code: 85 c0 74 dc 8b 0d 2b ca 3c 0f 85 c9 75 3d 45 85 ed 0f 85 b0 07 00 00 0f b7 43 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 4b 2c 85 14 <0f> 83 ea 0a 00 00 48 8d 04 80 48 8d 04 80 48 8d 04 c5 e0 0d 6b 96
RSP: 0018:ffffc90000007d48 EFLAGS: 00000007
RAX: 0000000000000071 RBX: ffff888025ea8bc8 RCX: 0000000000000000
RDX: 00000000ffe2f3a6 RSI: 0000000010f50544 RDI: 000000009dc59b3c
RBP: ffff888025ea8000 R08: 00000000ffffffff R09: 0000000000000071
R10: 0000000000000001 R11: 0000000000000000 R12: bc101d9a73125dae
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888123ddc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056516c7abbe0 CR3: 000000005afed000 CR4: 00000000003526f0
Call Trace:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:174
__run_hrtimer kernel/time/hrtimer.c:2036 [inline]
__hrtimer_run_queues+0x1b7/0x9c0 kernel/time/hrtimer.c:2096
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 56 f0 27 f6 48 89 df e8 de 3f 28 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 4f 17 f6 65 8b 05 ee 38 a6 08 85 c0 74 16 5b
RSP: 0018:ffffc90003c177b8 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffffffff9b9289b8 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff8e1a5b18 RDI: ffffffff8c401580
RBP: 0000000000000202 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88807624fbc0 R15: 1ffff92000782efe
debug_object_active_state+0x2ea/0x3f0 lib/debugobjects.c:1127
debug_rcu_head_queue kernel/rcu/rcu.h:237 [inline]
__call_rcu_common.constprop.0+0x4e/0x9b0 kernel/rcu/tree.c:3144
slab_free_hook mm/slub.c:2641 [inline]
slab_free mm/slub.c:6377 [inline]
kmem_cache_free+0x43e/0x6b0 mm/slub.c:6504
anon_vma_free mm/rmap.c:137 [inline]
__put_anon_vma+0x114/0x3a0 mm/rmap.c:2917
put_anon_vma mm/internal.h:215 [inline]
unlink_anon_vmas+0x5f3/0x8e0 mm/rmap.c:536
free_pgtables+0x2e7/0xd80 mm/memory.c:414
exit_mmap+0x44c/0xa00 mm/mmap.c:1312
__mmput+0x12a/0x410 kernel/fork.c:1187
mmput+0x67/0x80 kernel/fork.c:1210
exit_mm kernel/exit.c:615 [inline]
do_exit+0x8b1/0x2ae0 kernel/exit.c:997
do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
__do_sys_exit_group kernel/exit.c:1163 [inline]
__se_sys_exit_group kernel/exit.c:1161 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1161
x64_sys_call+0x102c/0x1530 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7cf4a286c5
Code: Unable to access opcode bytes at 0x7f7cf4a2869b.
RSP: 002b:00007ffef58fede8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000056516c908660 RCX: 00007f7cf4a286c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 000056516c5712c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffef58fee30 R14: 0000000000000000 R15: 0000000000000000
task:syz.2.911 state:R running task stack:27256 pid:9538 tgid:9531 ppid:5609 task_flags:0x40044c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872
Code: 05 fb 4d 7e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 86 81 3c 0f 0f 82 ac 02 00 00 8b 35 4e b5 3c 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d 4d 7e 12 0f 85 ec 02 00 00 48 83 c4
RSP: 0000:ffffc900053ef398 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e17fc5f RDI: ffffffff8c401580
RBP: ffffffff8ebe8180 R08: 000000000b2d5154 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
__call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3159
slab_free_hook mm/slub.c:2641 [inline]
slab_free mm/slub.c:6377 [inline]
kmem_cache_free+0x43e/0x6b0 mm/slub.c:6504
tear_down_vmas+0x2a5/0x600 mm/mmap.c:1262
exit_mmap+0x469/0xa00 mm/mmap.c:1320
__mmput+0x12a/0x410 kernel/fork.c:1187
mmput+0x67/0x80 kernel/fork.c:1210
exit_mm kernel/exit.c:615 [inline]
do_exit+0x8b1/0x2ae0 kernel/exit.c:997
do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb19459de99
RSP: 002b:00007fb1954bd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fb194826188 RCX: 00007fb19459de99
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fb194826188
RBP: 00007fb194826180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb194826218 R14: 00007fffcba9d600 R15: 00007fffcba9d6e8
task:udevd state:R running task stack:24632 pid:5622 tgid:5622 ppid:4976 task_flags:0x400140 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7413
preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190
spin_unlock include/linux/spinlock.h:390 [inline]
wp_page_copy mm/memory.c:3976 [inline]
do_wp_page+0x13d2/0x4350 mm/memory.c:4336
handle_pte_fault mm/memory.c:6395 [inline]
__handle_mm_fault+0x1ab6/0x2a00 mm/memory.c:6517
handle_mm_fault+0x37b/0xa30 mm/memory.c:6686
do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1343
handle_page_fault arch/x86/mm/fault.c:1483 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1536
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x7f7cf49ecdb7
RSP: 002b:00007ffef58fed20 EFLAGS: 00010202
RAX: 0000000000006010 RBX: 00000000000001f0 RCX: 000056516c7a5fe0
RDX: 0000000000006010 RSI: 000056516c79ffd0 RDI: 00007f7cf4b28ac0
RBP: 00007f7cf4b28ac0 R08: 00000000000001f0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000056516c79ffd0
R13: 00007f7cf4b28ac0 R14: 00000000000001f0 R15: 00007f7cf4b28ac0
rcu: rcu_preempt kthread starved for 10502 jiffies! g47353 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:27672 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: d6 8b 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 7e 10 00 fb f4 bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197e00 EFLAGS: 00000246
RAX: 000000000447d211 RBX: ffff88801eaca540 RCX: ffffffff8bbb22d5
RDX: 0000000000000000 RSI: ffffffff8e1a5b18 RDI: ffffffff8c401580
RBP: ffffed1003d594a8 R08: 0000000000000001 R09: ffffed10170a678d
R10: ffff8880b8533c6b R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888123edc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555815b1a48 CR3: 000000007f30d000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:768
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x158