rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-...!: (10500 ticks this GP) idle=79b/1/0x4000000000000000 softirq=8962/8962 fqs=4
(t=10502 jiffies g=11437 q=236)
rcu: rcu_preempt kthread starved for 10495 jiffies! g11437 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:27800 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
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:2117
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
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: 4660 Comm: syz.5.29 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline]
RIP: 0010:lock_acquire+0xc1/0x400 kernel/locking/lockdep.c:5594
Code: 08 0f 83 a2 01 00 00 44 89 f0 c1 e8 06 48 8d 3c c5 28 f0 89 8d be 08 00 00 00 e8 8a 43 61 00 44 89 f0 48 0f a3 05 b7 de 2c 0c <73> 0d e8 a8 ce 07 00 84 c0 0f 84 2d 02 00 00 48 c7 c0 c4 23 8a 8d
RSP: 0018:ffffc9000302f7e0 EFLAGS: 00000057
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff815d1166
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d89f028
RBP: ffffc9000302f8e8 R08: ffffffff8d89f02f R09: 1ffffffff1b13e05
R10: dffffc0000000000 R11: fffffbfff1b13e06 R12: ffffffff8c331308
R13: 1ffff92000605f08 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000555584c1c500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000005ae22000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
seqcount_lockdep_reader_access+0xcd/0x1d0 include/linux/seqlock.h:103
timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
timekeeping_get_ns kernel/time/timekeeping.c:388 [inline]
ktime_get+0x7b/0x270 kernel/time/timekeeping.c:831
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+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: 0033:0x7f6e063a2212
Code: 24 08 48 8b 7c 24 08 e8 ac a0 14 00 bf 40 0d 03 00 89 c3 e8 f0 c6 14 00 48 83 c4 10 48 63 c3 5b c3 0f 1f 80 00 00 00 00 41 54 <55> 53 48 89 fb 48 81 ec d0 00 00 00 48 89 74 24 28 48 89 54 24 30
RSP: 002b:00007ffda22ce5f0 EFLAGS: 00000212
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6e0659d20c
RDX: 000000000000d1f8 RSI: 0000000000000000 RDI: 00007f6e06584735
RBP: 00007f6e0659d20c R08: 0000000000000000 R09: 000700397d19c7f8
R10: 0000007de9213e50 R11: 000000000000acb4 R12: 0000000000000000
R13: 00007f6e06766fac R14: 00007f6e06766fa0 R15: 00007f6e06766fa0
NMI backtrace for cpu 1
CPU: 1 PID: 4655 Comm: syz.4.31 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
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:2021
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+0x4b4/0xb70 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
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:93 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x2a/0x70 kernel/entry/common.c:114
Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 3d f6 ff ff eb 31 eb 35 e8 74 8d c2 f7 e8 6f 8b c2 f7 fb 65 48 8b 05 d6 9a 45 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 11 8b aa f7 48
RSP: 0018:ffffc9000263ff08 EFLAGS: 00000286
RAX: ffff88802c910000 RBX: 000000000000000f RCX: c8862d9cba6c5f00
RDX: dffffc0000000000 RSI: ffffffff8a2b2800 RDI: ffffffff8a79fe00
RBP: ffffc9000263ff48 R08: ffffffff8d89f02f R09: 1ffffffff1b13e05
R10: dffffc0000000000 R11: fffffbfff1b13e06 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc9000263ff58 R15: 0000000000000000
do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f0ca0c33159
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:00007ffcacb55b00 EFLAGS: 00000206 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f0ca0f0afa0 RCX: 00007f0ca0c33159
RDX: 00007ffcacb55b00 RSI: 00007ffcacb55c30 RDI: 0000000000000021
RBP: 00007f0ca0d27d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f0ca0f0afac R14: 00007f0ca0f0afa0 R15: 00007f0ca0f0afa0
sched: RT throttling activated