rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=c85/0/0x1 softirq=28649/28649 fqs=0 
	(t=10501 jiffies g=36837 q=3)
rcu: rcu_preempt kthread starved for 10502 jiffies! g36837 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:27984 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: 10439 Comm: syz.6.1549 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:mark_usage kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:__lock_acquire+0xd47/0x7d10 kernel/locking/lockdep.c:4966
Code: b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 0f 85 5e 61 00 00 83 3b 00 74 22 4c 89 ef 4c 89 fe ba 06 00 00 00 e8 59 a6 00 00 <49> b8 00 00 00 00 00 fc ff df 85 c0 0f 84 06 4d 00 00 4c 89 ef 4c
RSP: 0018:ffffc90003f0f8e0 EFLAGS: 00000082
RAX: 0000000000000001 RBX: ffff888022db4650 RCX: ffffffff815dbb94
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d10f0
RBP: ffffc90003f0fb30 R08: ffffffff901d10f7 R09: 1ffffffff203a21e
R10: dffffc0000000000 R11: fffffbfff203a21f R12: ffff888022db4690
R13: ffff888022db3b80 R14: 0000000000000000 R15: ffff888022db4670
FS:  00007fb0336d46c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000004cad0000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __might_fault+0xb3/0x110 mm/memory.c:5357
 _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: 0033:0x7fb03541a0d9
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:00007fb0336d3a80 EFLAGS: 00000202 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007fb0356f3fa0 RCX: 00007fb03541a0d9
RDX: 00007fb0336d3a80 RSI: 00007fb0336d3bb0 RDI: 0000000000000021
RBP: 00007fb0354e6bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fb0356f4038 R14: 00007fb0356f3fa0 R15: 00007ffda2b83eb8
 </TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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:default_idle+0xb/0x10 arch/x86/kernel/process.c:730
Code: b7 48 89 df e8 f6 ea f8 f7 eb ad e8 8f af f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d b7 96 60 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffc90000d67d48 EFLAGS: 000002c2
RAX: 1219dcaf7a082400 RBX: ffff88813fe68000 RCX: 1219dcaf7a082400
RDX: 0000000000000001 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780
RBP: ffffc90000d67e80 R08: ffff8880b913b30b R09: 1ffff11017227661
R10: dffffc0000000000 R11: ffffed1017227662 R12: 1ffff11027fcd000
R13: dffffc0000000000 R14: 0000000000000001 R15: 1ffff920001acfb4
 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x21f/0x580 kernel/sched/idle.c:306
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
 start_secondary+0x330/0x430 arch/x86/kernel/smpboot.c:281
 secondary_startup_64_no_verify+0xb1/0xbb
 </TASK>