rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=92729, q=34 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295029452-4295018949), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10504 jiffies! g92729 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:27656 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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: 15265 Comm: syz.6.2020 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:same_thread_group include/linux/sched/signal.h:715 [inline]
RIP: 0010:send_sigqueue+0x185/0x710 kernel/signal.c:2007
Code: 74 77 44 89 f5 65 4c 8b 35 98 04 af 7e 49 8d 9d 10 09 00 00 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 eb aa 8a 00 <4c> 8b 3b 49 8d 9e 10 09 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00
RSP: 0018:ffffc900001f0c78 EFLAGS: 00000046
RAX: 1ffff1100495dc62 RBX: ffff888024aee310 RCX: 0000000000010000
RDX: ffff88802b9e1e00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff22386a0
R10: dffffc0000000000 R11: fffffbfff22386a1 R12: ffff888061fe08c0
R13: ffff888024aeda00 R14: ffff88802b9e1e00 R15: dffffc0000000000
FS:  00007f4b22b886c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3d37c9 CR3: 0000000064312000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 posix_timer_event kernel/time/posix-timers.c:299 [inline]
 posix_timer_fn+0x16e/0x3d0 kernel/time/posix-timers.c:325
 __run_hrtimer kernel/time/hrtimer.c:1750 [inline]
 __hrtimer_run_queues+0x520/0xc40 kernel/time/hrtimer.c:1814
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
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: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 5a fd d8 f6 48 89 df e8 12 d2 d9 f6 e8 dd e2 fd f6 fb bf 01 00 00 00 <e8> f2 d8 cc f6 65 8b 05 63 06 74 75 85 c0 74 02 5b c3 e8 e0 ed 70
RSP: 0018:ffffc9000f577c78 EFLAGS: 00000286
RAX: 0036e3c9d72ebf00 RBX: ffff88805cda1280 RCX: 0036e3c9d72ebf00
RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: 0000000000000001
RBP: ffff88805cda1718 R08: ffffffff8e8b02af R09: 1ffffffff1d16055
R10: dffffc0000000000 R11: fffffbfff1d16056 R12: 1ffff1100b9b42e3
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x11f5/0x13f0 kernel/signal.c:2905
 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
 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:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4b21d9c797
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007f4b22b880e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f4b22015fa8 RCX: 00007f4b21d9c799
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4b22015fa8
RBP: 00007f4b22015fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4b22016038 R14: 00007ffc46f1a9f0 R15: 00007ffc46f1aad8
 </TASK>