rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10511 ticks this GP) idle=d994/1/0x4000000000000000 softirq=10696/10767 fqs=27
	(t=10502 jiffies g=10377 q=2408 ncpus=2)
rcu: rcu_preempt kthread starved for 10449 jiffies! g10377 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:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </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 PID: 4525 Comm: syz.2.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:lock_is_held_type+0x92/0x190 kernel/locking/lockdep.c:5705
Code: fa 48 c7 c7 60 12 8c 8a e8 eb 12 00 00 65 ff 05 a4 a4 ea 75 83 bb d8 0a 00 00 00 7e 4b 44 89 fd 49 89 df 49 81 c7 e0 0a 00 00 <45> 31 e4 49 83 fc 31 73 24 4c 89 ff 4c 89 f6 e8 2a 02 00 00 85 c0
RSP: 0018:ffffc900001e0bc0 EFLAGS: 00000082
RAX: 0000000000000001 RBX: ffff88807c3e8000 RCX: 8cbe21bc17ffa500
RDX: ffff88807c3e8000 RSI: ffffffff8a8c1260 RDI: ffffffff8adef760
RBP: 00000000ffffffff R08: dffffc0000000000 R09: fffffbfff215c449
R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: ffff88805e3765c0
R13: 0000000000000046 R14: ffffffff8cb2aca0 R15: ffff88807c3e8ae0
FS:  000055555f227500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ef63fff CR3: 0000000026e1d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __lock_task_sighand+0x110/0x2d0 kernel/signal.c:1396
 lock_task_sighand include/linux/sched/signal.h:745 [inline]
 send_sigqueue+0x159/0x600 kernel/signal.c:1979
 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:1747 [inline]
 __hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1811
 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 8f 41 f7 48 89 df e8 e6 54 42 f7 e8 31 48 65 f7 fb bf 01 00 00 00 <e8> 76 cd 35 f7 65 8b 05 f7 84 e0 75 85 c0 74 02 5b c3 e8 44 96 de
RSP: 0018:ffffc90003857b98 EFLAGS: 00000282
RAX: 8cbe21bc17ffa500 RBX: ffff88805e3765c0 RCX: 8cbe21bc17ffa500
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: 0000000000000001
RBP: ffff88805e376858 R08: dffffc0000000000 R09: ffffed100bc6ecb9
R10: ffffed100bc6ecb9 R11: 1ffff1100bc6ecb8 R12: 1ffff1100bc6ed0b
R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x1163/0x1350 kernel/signal.c:2874
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb96045ee7a
Code: 50 e8 03 00 00 4c 8b 34 24 49 89 d8 48 ba db 34 b6 d7 82 de 1b 43 48 89 d0 48 f7 64 24 58 48 8d 3d 13 65 1b 00 31 c0 41 8b 36 <48> c1 ea 12 48 01 ca 48 89 e9 48 2b 15 5d 68 eb 00 e8 e0 f0 fe ff
RSP: 002b:00007ffd251fdee0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000033068
RDX: 0000000006e02e84 RSI: 0000000000000000 RDI: 00007fb960615388
RBP: 00007fb96062d196 R08: 0000000000000000 R09: 001947d637232824
R10: 0000006d82a49a04 R11: 00000000000092ee R12: 0000000000000000
R13: 00007fb9607e5fa0 R14: 00007fb9607e5fa0 R15: 0000000000000004
 </TASK>
CPU: 0 PID: 4524 Comm: syz.1.23 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 8f 41 f7 48 89 df e8 e6 54 42 f7 e8 31 48 65 f7 fb bf 01 00 00 00 <e8> 76 cd 35 f7 65 8b 05 f7 84 e0 75 85 c0 74 02 5b c3 e8 44 96 de
RSP: 0018:ffffc90003877b98 EFLAGS: 00000282
RAX: c04a88ec1d354700 RBX: ffff888074985340 RCX: c04a88ec1d354700
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: 0000000000000001
RBP: ffff8880749855d8 R08: dffffc0000000000 R09: ffffed100e930a69
R10: ffffed100e930a69 R11: 1ffff1100e930a68 R12: 1ffff1100e930abb
R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000
FS:  0000555568e0b500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ee63fff CR3: 000000007c80d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x1163/0x1350 kernel/signal.c:2874
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1ed5f8f749
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:00007ffef1537ab8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 000000000001ec27 RCX: 00007f1ed5f8f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 00000004f1537daf
R10: 0000001b2e220000 R11: 0000000000000246 R12: 00007f1ed61e5fac
R13: 00007f1ed61e5fa0 R14: ffffffffffffffff R15: 0000000000000004
 </TASK>