rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=523/1/0x4000000000000000 softirq=6769/6770 fqs=3 
	(t=10500 jiffies g=6973 q=253)
rcu: rcu_preempt kthread starved for 10494 jiffies! g6973 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:27880 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 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: 4429 Comm: syz.2.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__lock_acquire+0x85/0x7c60 kernel/locking/lockdep.c:4870
Code: 84 24 28 01 00 00 d2 37 b0 8b 48 c7 84 24 30 01 00 00 20 ff 5b 81 48 8d 8c 24 20 01 00 00 48 c1 e9 03 42 c7 04 01 f1 f1 f1 f1 <48> b8 f2 f2 f2 f2 f2 00 00 00 4a 89 44 01 0b 42 c7 44 01 17 f3 f3
RSP: 0018:ffffc90003c0f560 EFLAGS: 00000802
RAX: 8da9a1ad70d38b00 RBX: ffffffff8c12ef08 RCX: 1ffff92000781ed0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c12ef08
RBP: ffffc90003c0f7b0 R08: dffffc0000000000 R09: 0000000000000001
R10: fffffbfff1ad26b6 R11: 1ffffffff1ad26b5 R12: 0000000000000001
R13: 1ffff92000781f08 R14: 0000000000000000 R15: 0000000000000001
FS:  000055558f88d500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000002b795000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 seqcount_lockdep_reader_access+0xc6/0x1c0 include/linux/seqlock.h:103
 ktime_get+0x31/0x270 kernel/time/timekeeping.c:829
 clockevents_program_min_delta+0x55/0x340 kernel/time/clockevents.c:241
 hrtimer_start_range_ns+0xa9a/0xc20 kernel/time/hrtimer.c:1287
 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+0xc1/0x1300 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: 0033:0x7f7555fea749
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:00007ffe4a7b9da8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f7556240fa0 RCX: 00007f7555fea749
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f755606ef91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7556240fa0 R14: 00007f7556240fa0 R15: 0000000000000004
 </TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 4428 Comm: syz.0.23 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 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+0x6d8/0x1110 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+0x4fe/0xc40 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:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc90003befa80 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: bdcfa4afec35a100
RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800
RBP: ffffc90003befba0 R08: dffffc0000000000 R09: fffffbfff1ff541f
R10: fffffbfff1ff541f R11: 1ffffffff1ff541e R12: ffff88802befce28
R13: 1ffff9200077df5c R14: 0000000000000246 R15: dffffc0000000000
 __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_altstack+0x9a/0x360 kernel/signal.c:4252
 __ia32_sys_rt_sigreturn+0x660/0x790 arch/x86/kernel/signal.c:677
 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: 0033:0x7f8033852749
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:00007ffd28990a78 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f8033aa8fa0 RCX: 00007f8033852749
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f80338d6f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8033aa8fa0 R14: 00007f8033aa8fa0 R15: 0000000000000004
 </TASK>
sched: RT throttling activated