rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=14401, q=648 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294962116-4294951614), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g14401 f0x2 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:27744 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5030 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6817 Comm: syz.2.229 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
RIP: 0010:lock_release+0xa7/0x3d0 kernel/locking/lockdep.c:5888
Code: 00 00 00 0f 85 1e 02 00 00 49 81 3e c0 13 3a 93 0f 84 11 02 00 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 48 8b 5c 24 20 fa <48> c7 c7 f2 3e 7a 8d e8 cd 47 bd 09 65 ff 05 36 fe d7 10 c7 44 24
RSP: 0018:ffffc90000a08b78 EFLAGS: 00000083
RAX: 0000000000000000 RBX: 0000000000000083 RCX: 7ea49cd9de4f6100
RDX: 0000000000010000 RSI: ffffffff8bbf81c0 RDI: ffffffff8bbf8180
RBP: ffffc90000a08c70 R08: ffffffff8f7deb77 R09: 1ffffffff1efbd6e
R10: dffffc0000000000 R11: fffffbfff1efbd6f R12: dffffc0000000000
R13: ffffffff8187dd0b R14: ffff888031a23798 R15: ffff888030581e80
FS:  00007f4ba2dfe6c0(0000) GS:ffff888125fba000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4ba2dfe040 CR3: 00000000780a4000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 unlock_task_sighand include/linux/sched/signal.h:756 [inline]
 posixtimer_send_sigqueue+0x48b/0xa70 kernel/signal.c:2084
 posix_timer_queue_signal kernel/time/posix-timers.c:364 [inline]
 posix_timer_fn+0x121/0x1c0 kernel/time/posix-timers.c:379
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x51c/0xc70 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x410 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
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 8a 34 40 f6 48 89 df e8 c2 cb 40 f6 e8 9d 3f 6b f6 fb bf 01 00 00 00 <e8> 32 b6 32 f6 65 8b 05 db ed 17 07 85 c0 74 07 5b e9 81 4d 00 00
RSP: 0018:ffffc9000c007c60 EFLAGS: 00000286
RAX: 7ea49cd9de4f6100 RBX: ffff888031a23780 RCX: 7ea49cd9de4f6100
RDX: 0000000000000000 RSI: ffffffff8d78f71d RDI: 0000000000000001
RBP: 0000000000000011 R08: ffffffff8f7deb77 R09: 1ffffffff1efbd6e
R10: dffffc0000000000 R11: fffffbfff1efbd6f R12: 1ffff11006344743
R13: 0000000000000000 R14: 0000000004000000 R15: ffff888031a23a18
 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+0x2e9/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4ba378f749
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:00007f4ba2dfe0e8 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 00007f4ba39e5fa8 RCX: 00007f4ba378f749
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f4ba39e5fac
RBP: 00007f4ba39e5fa0 R08: 3fffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4ba39e6038 R14: 00007ffc4c140fe0 R15: 00007ffc4c1410c8
 </TASK>