rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=dc74/1/0x4000000000000000 softirq=30610/30614 fqs=5
rcu: (detected by 0, t=10502 jiffies, g=24941, q=931 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 9581 Comm: syz.3.950 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__lock_acquire+0x7e/0xd20 kernel/locking/lockdep.c:5106
Code: 0f 45 c8 89 4c 24 0c 8b 0d af 6d dc 17 85 c9 0f 95 c0 83 fe 08 0f 92 c2 08 c2 0f 84 55 01 00 00 44 89 cd 83 fe 01 48 89 3c 24 <77> 0c 89 f0 48 8b 44 c3 08 48 85 c0 75 20 45 31 ff 48 89 df 31 d2
RSP: 0018:ffffc90000a08ad0 EFLAGS: 00000097
RAX: ffffffff99981800 RBX: ffffffff999d29a8 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88802d34dac0
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
R10: ffffc90000a08cb0 R11: fffff52000141198 R12: 0000000000000000
R13: ffffffff999d29a8 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126238000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efc41a9edd0 CR3: 000000000dd38000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873
debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:483
__run_hrtimer kernel/time/hrtimer.c:1745 [inline]
__hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680
Code: c7 a0 70 68 8b be 80 03 00 00 48 c7 c2 40 71 68 8b e8 56 d7 29 00 48 c7 c7 e0 d6 f3 8d 4c 89 fe e8 37 bd 29 00 e8 c2 63 33 00 <89> d8 48 81 c4 98 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc
RSP: 0018:ffffc90003c8f3d8 EFLAGS: 00000287
RAX: 0000000000000000 RBX: ffffffff900b8101 RCX: 1060b7fc1afb6f00
RDX: 0000000000000000 RSI: ffffffff8d8f5ae9 RDI: ffff88802d34dac0
RBP: dffffc0000000000 R08: ffffc90003c8fc30 R09: 0000000000000000
R10: ffffc90003c8f4f8 R11: fffff52000791ea1 R12: ffffc90003c8fc40
R13: ffffc90003c88000 R14: ffffc90003c8f4a8 R15: ffffffff81738c45
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
task_work_add+0xb1/0x420 kernel/task_work.c:65
__fput_deferred+0x154/0x390 fs/file_table.c:529
fput_close+0x119/0x200 fs/file_table.c:585
filp_close+0x27/0x40 fs/open.c:1563
close_files fs/file.c:494 [inline]
put_files_struct+0x1ba/0x350 fs/file.c:509
do_exit+0x66f/0x2300 kernel/exit.c:961
do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f21aff8f749
Code: Unable to access opcode bytes at 0x7f21aff8f71f.
RSP: 002b:00007f21b0d9e038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: 00000000000000c8 RBX: 00007f21b01e5fa0 RCX: 00007f21aff8f749
RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 0000000000000007
RBP: 00007f21b0013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f21b01e6038 R14: 00007f21b01e5fa0 R15: 00007fff22c42438
rcu: rcu_preempt kthread starved for 10492 jiffies! g24941 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:27912 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
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+0x4bc/0x870 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: 0 UID: 0 PID: 5927 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 e6 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 91 6f 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 75 6f
RSP: 0018:ffffc900052b7640 EFLAGS: 00000293
RAX: ffffffff81b4943b RBX: 1ffff11017127ffd RCX: ffff88802ea7bc80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900052b77c0 R08: ffffffff8f7cf477 R09: 1ffffffff1ef9e8e
R10: dffffc0000000000 R11: fffffbfff1ef9e8f R12: ffff8880b893ffe8
R13: dffffc0000000000 R14: ffff8880b883b240 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888126138000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff8613156c0 CR3: 000000000dd38000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2713 [inline]
smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2923
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:852
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245