rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (10499 ticks this GP) idle=3c3/1/0x4000000000000000 softirq=7055/7055 fqs=5
(t=10501 jiffies g=8733 q=588)
rcu: rcu_preempt kthread starved for 10492 jiffies! g8733 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:27008 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
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
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: 4436 Comm: syz.4.21 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:lockdep_softirqs_on+0x13f/0x570 kernel/locking/lockdep.c:4415
Code: 41 83 3e 00 0f 85 fa 01 00 00 48 89 fb 48 c7 c7 20 26 0b 8a e8 12 73 4d 08 48 ba 00 00 00 00 00 fc ff df 65 ff 05 91 ac a6 7e <41> 0f b6 04 17 84 c0 0f 85 4d 03 00 00 4d 8d b5 88 0a 00 00 41 c7
RSP: 0018:ffffc90003e1fb60 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffffffff812ba7d5 RCX: a573a5674809aa00
RDX: dffffc0000000000 RSI: ffffffff8a0b2620 RDI: ffffffff8a59a4c0
RBP: ffffc90003e1fc10 R08: dffffc0000000000 R09: ffffed100b3e9771
R10: ffffed100b3e9771 R11: 1ffff1100b3e9770 R12: 1ffff920007c3f70
R13: ffff888059f4bb80 R14: ffff888059f4c650 R15: 1ffff1100b3e98ca
FS: 00005555861ce500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 00000000208fd000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__local_bh_enable_ip+0xe6/0x1b0 kernel/softirq.c:389
handle_signal arch/x86/kernel/signal.c:840 [inline]
arch_do_signal_or_restart+0xf18/0x1300 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: 0033:0x7f67996d1600
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d ca 3c 08 00 e8 d5 8e f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007ffc26961238 EFLAGS: 00000203
RAX: 0000000000000000 RBX: 00007f67998fffa0 RCX: 00007f67998fffa0
RDX: 00007ffc26961240 RSI: 00007ffc26961370 RDI: 0000000000000021
RBP: 00007f679972bf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f67998fffa0 R14: 00007f67998fffa0 R15: 0000000000000004
NMI backtrace for cpu 0
CPU: 0 PID: 4435 Comm: syz.1.23 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
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
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae dc a9 f7 48 89 df e8 76 b1 aa f7 e8 11 4b cb f7 fb bf 01 00 00 00 b6 d4 9e f7 65 8b 05 97 d2 4f 76 85 c0 74 02 5b c3 e8 44 dd 4d
RSP: 0018:ffffc90003d9fbc0 EFLAGS: 00000282
RAX: b0192a8356eaae00 RBX: ffff88807c9365c0 RCX: b0192a8356eaae00
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: 0000000000000001
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100f926cb9
R10: ffffed100f926cb9 R11: 1ffff1100f926cb8 R12: ffff88807c9365c0
R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004
spin_unlock_irq include/linux/spinlock.h:413 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
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: 0033:0x7fd695cb4b72
Code: e8 a3 c1 0c 00 85 c0 0f 84 93 01 00 00 64 f0 83 2c 25 90 ff ff ff 01 e8 ec 9b 0b 00 48 8b 0c 24 8b 00 48 83 b9 88 00 00 00 ff <89> 81 90 00 00 00 75 04 85 c0 74 1e 48 63 54 24 10 48 89 d0 48 c1
RSP: 002b:00007ffc2dd0e120 EFLAGS: 00000213
RAX: 000000000000000e RBX: 00007fd69603bfa0 RCX: 00007fd69603bfa0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00007fd695e67f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd69603bfa0 R14: 00007fd69603bfa0 R15: 0000000000000004