rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10497 ticks this GP) idle=94f/1/0x4000000000000000 softirq=31036/31036 fqs=51 
	(t=10502 jiffies g=35817 q=72)
rcu: rcu_preempt kthread starved for 10399 jiffies! g35817 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:28016 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </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: 12336 Comm: syz.3.2069 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:192 [inline]
RIP: 0010:__lock_acquire+0x12bc/0x7d10 kernel/locking/lockdep.c:5009
Code: 00 00 74 12 48 89 df e8 b2 13 61 00 49 b8 00 00 00 00 00 fc ff df 48 83 3b 00 0f 84 f0 49 00 00 48 8b 44 24 58 42 0f b6 04 00 <84> c0 0f 85 b2 5a 00 00 41 8b 07 89 c3 81 e3 ff 1f 00 00 c1 e8 03
RSP: 0018:ffffc9000449f660 EFLAGS: 00000086
RAX: 0000000000000000 RBX: ffffffff8fbe7800 RCX: ffffffff815d16fe
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d2238
RBP: ffffc9000449f8b0 R08: dffffc0000000000 R09: 1ffffffff203a447
R10: dffffc0000000000 R11: fffffbfff203a448 R12: 000000004903e6a2
R13: ffff88807ee23b80 R14: 00000000e25ba5d2 R15: ffff88807ee246b8
FS:  00007f6bcfe1f6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 0000000054d3f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
 lock_hrtimer_base kernel/time/hrtimer.c:168 [inline]
 hrtimer_start_range_ns+0xff/0xc20 kernel/time/hrtimer.c:1284
 posixtimer_rearm+0x131/0x340 kernel/time/posix-timers.c:329
 dequeue_signal+0x174/0x440 kernel/signal.c:696
 get_signal+0x6fe/0x12c0 kernel/signal.c:2781
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6bd1bc4f77
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:00007f6bcfe1f0e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f6bd1e3efa8 RCX: 00007f6bd1bc4f79
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6bd1e3efa8
RBP: 00007f6bd1e3efa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6bd1e3f038 R14: 00007fff3fb65530 R15: 00007fff3fb65618
 </TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 12333 Comm: syz.6.2067 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ea/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4ad/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:debug_lockdep_rcu_enabled+0x25/0x30 kernel/rcu/update.c:281
Code: 00 00 cc cc 00 31 c0 83 3d bb bd cd 03 00 74 1d 83 3d 32 f0 cd 03 00 74 14 65 48 8b 0d 24 51 46 76 31 c0 83 b9 ec 0a 00 00 00 <0f> 94 c0 c3 00 00 cc cc 00 00 cc 41 56 53 89 fb e8 16 0a 00 00 41
RSP: 0018:ffffc900043afb78 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff92000875f78 RCX: ffff888024091dc0
RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f740
RBP: ffffc900043afc88 R08: ffffc900043afe5f R09: ffffc900043afd60
R10: dffffc0000000000 R11: fffff52000875fcc R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8a79b9e0 R15: 0000000000000000
 ___might_sleep+0xd5/0x610 kernel/sched/core.c:9624
 __might_fault+0x6b/0x110 mm/memory.c:5354
 _copy_from_user+0x29/0x170 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:192 [inline]
 restore_sigcontext arch/x86/kernel/signal.c:91 [inline]
 __ia32_sys_rt_sigreturn+0x21d/0x760 arch/x86/kernel/signal.c:674
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2a8b796399
Code: 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 0c 25
RSP: 002b:00007f2a89a4ea80 EFLAGS: 00000202 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f2a8ba6efa0 RCX: 00007f2a8b796399
RDX: 00007f2a89a4ea80 RSI: 00007f2a89a4ebb0 RDI: 0000000000000021
RBP: 00007f2a8b88b7e0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f2a8ba6f038 R14: 00007f2a8ba6efa0 R15: 00007ffdd3dce318
 </TASK>