rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=e3f/1/0x4000000000000000 softirq=7526/7609 fqs=2 
	(t=10500 jiffies g=8657 q=738)
rcu: rcu_preempt kthread starved for 10496 jiffies! g8657 f0x0 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:28192 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4463 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:344 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:895 [inline]
RIP: 0010:trace_user_enter+0x51/0x190 include/trace/events/context_tracking.h:34
Code: 07 77 55 e8 c1 14 dc ff 41 89 de c1 eb 06 48 8d 3c dd a8 95 69 8d be 08 00 00 00 e8 49 7e 20 00 31 f6 4c 0f a3 35 f7 df cd 0b <0f> 92 c3 40 0f 92 c6 bf 02 00 00 00 e8 ee 16 dc ff 84 db 74 10 e8
RSP: 0018:ffffc9000396fee0 EFLAGS: 00000047
RAX: ffffffff819bb501 RBX: 0000000000000000 RCX: ffffffff819bb5a7
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8d6995a8
RBP: ffffc9000396ff48 R08: dffffc0000000000 R09: fffffbfff1ad32b6
R10: fffffbfff1ad32b6 R11: 1ffffffff1ad32b5 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000027
FS:  000055559364f500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000001ebb0000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __context_tracking_enter+0x58/0x90 kernel/context_tracking.c:81
 user_enter_irqoff include/linux/context_tracking.h:41 [inline]
 __exit_to_user_mode kernel/entry/common.c:136 [inline]
 syscall_exit_to_user_mode+0x3c/0x40 kernel/entry/common.c:309
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff50b5ded67
Code: 0b e9 68 fe ff ff 48 83 c4 18 48 8d 3d 32 6b d9 00 5b 5d 41 5c 41 5d 41 5e 41 5f e9 f3 f7 fb ff 0f 1f 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00
RSP: 002b:00007ffd46f29b48 EFLAGS: 00000206 ORIG_RAX: 0000000000000027
RAX: 0000000000000003 RBX: 00007ffd46f29cb0 RCX: 00007ff50b5ded67
RDX: 00007ffd46f29b80 RSI: 00007ffd46f29cb0 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000001b33020000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000206 R12: 00007ff50b83efac
R13: 00007ff50b83efa0 R14: ffffffffffffffff R15: 0000000000000004
 </TASK>
NMI backtrace for cpu 0
CPU: 0 PID: 4462 Comm: syz.1.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x13/0x60 kernel/kcov.c:206
Code: 48 8b 3d 90 cd f1 0b 48 89 de 5b e9 47 9e 43 00 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d 64 a5 8a 7e 65 8b 15 65 a5 8a 7e <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00
RSP: 0018:ffffc9000394fb18 EFLAGS: 00000246
RAX: ffffffff812bc1c7 RBX: dffffc0000000000 RCX: ffff888029fdd940
RDX: 0000000080000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000394fcb0 R08: dffffc0000000000 R09: ffffed10053fbdda
R10: ffffed10053fbdda R11: 1ffff110053fbdd9 R12: 0000000000000344
R13: 00007ffe52a5ea40 R14: ffff888029fdd940 R15: 0000000000000000
 copy_fpstate_to_sigframe+0x107/0xb90 arch/x86/kernel/fpu/signal.c:189
 get_sigframe arch/x86/kernel/signal.c:295 [inline]
 __setup_rt_frame arch/x86/kernel/signal.c:471 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
 handle_signal arch/x86/kernel/signal.c:824 [inline]
 arch_do_signal_or_restart+0x67a/0x1300 arch/x86/kernel/signal.c:869
 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: 0033:0x7f5573e28ec9
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:00007ffe52a5ee08 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f557407ffa8 RCX: 00007f5573e28ec9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f557407ffac
RBP: 0000000000000000 R08: 000ca0aeb0a87dc2 R09: 0000000652a5f0ff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f557407ffac
R13: 00007f557407ffa0 R14: 0000000000001da6 R15: 0000000000000004
 </TASK>