rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=64041, q=148 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295059341-4295048838), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10505 jiffies! g64041 f0x2 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:26920 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12891 Comm: syz.9.1320 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0xc4/0x410 kernel/locking/lockdep.c:5725
Code: 7e 83 f8 08 0f 83 8a 01 00 00 41 89 c6 c1 e8 06 48 8d 3c c5 68 83 4a 8e be 08 00 00 00 e8 b4 ef 75 00 4c 0f a3 35 d4 8e e3 0c <73> 0d e8 f5 9f 08 00 84 c0 0f 84 18 02 00 00 48 c7 c0 1c b8 4a 8e
RSP: 0018:ffffc90000007b00 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8166f48c
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a8368
RBP: ffffc90000007c18 R08: ffffffff8e4a836f R09: 1ffffffff1c9506d
R10: dffffc0000000000 R11: fffffbfff1c9506e R12: 1ffff92000000f6c
R13: ffffffff8cd2ff20 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000555555766500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffeb5790bc0 CR3: 000000002e68e000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 __lock_task_sighand+0x46/0x2d0 kernel/signal.c:1407
 lock_task_sighand include/linux/sched/signal.h:742 [inline]
 send_sigqueue+0x239/0x710 kernel/signal.c:2009
 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+0x51e/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:preempt_latency_start kernel/sched/core.c:5828 [inline]
RIP: 0010:preempt_count_add+0xa6/0x1a0 kernel/sched/core.c:5851
Code: ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 48 89 df e8 2f c6 0c 00 85 c0 74 09 31 db 31 ff e8 22 c6 0c 00 65 4c 8b 35 da 4b a8 7e <49> 81 c6 c8 14 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c
RSP: 0018:ffffc9000e32fd80 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff812dd77d RCX: ffffffff96eae400
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff812dd77d
RBP: ffffc9000e32fec0 R08: ffff8880229b0007 R09: 1ffff11004536000
R10: dffffc0000000000 R11: ffffed1004536001 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff8880229b0000 R15: dffffc0000000000
 rseq_signal_deliver include/linux/sched.h:2364 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:212 [inline]
 handle_signal arch/x86/kernel/signal.c:267 [inline]
 arch_do_signal_or_restart+0x2ed/0x780 arch/x86/kernel/signal.c:312
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 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+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f202998eec9
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:00007ffeb5790d88 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00000000001106d2 RCX: 00007f202998eec9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f2029be5fac
RBP: 0000000000000032 R08: 0000000000746c03 R09: 00000015b579107f
R10: 00007ffeb5790e80 R11: 0000000000000246 R12: 00007f2029be5fac
R13: 00007ffeb5790e80 R14: 0000000000110704 R15: 00007ffeb5790ea0
 </TASK>