rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (1 GPs behind) idle=693/1/0x4000000000000000 softirq=7269/7279 fqs=3
(t=10500 jiffies g=8705 q=596)
rcu: rcu_preempt kthread starved for 10493 jiffies! g8705 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:28176 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4380 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3681 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3701 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3756 [inline]
RIP: 0010:__lock_acquire+0x141b/0x7d10 kernel/locking/lockdep.c:5012
Code: c6 03 00 00 48 b8 eb 83 b5 80 46 86 c8 61 49 0f af c4 48 c1 e8 2d 48 8d 1c c5 00 50 d4 8f 48 89 d8 48 c1 e8 03 48 89 44 24 50 <42> 80 3c 00 00 74 12 48 89 df e8 46 29 61 00 49 b8 00 00 00 00 00
RSP: 0018:ffffc90000dd0a60 EFLAGS: 00000806
RAX: 1ffffffff2026f82 RBX: ffffffff90137c10 RCX: ffffffff815d29ac
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d50c8
RBP: ffffc90000dd0cb0 R08: dffffc0000000000 R09: 1ffffffff203aa19
R10: dffffc0000000000 R11: fffffbfff203aa1a R12: abe92a66ad81a2ce
R13: ffff88801dd88000 R14: 00000000ad81a2ce R15: ffff88801dd88b10
FS: 00007ff2dc8746c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000007b15f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
hrtimer_interrupt+0xf8/0x8d0 kernel/time/hrtimer.c:1792
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: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be 59 97 f7 48 89 df e8 f6 31 98 f7 e8 01 27 b9 f7 fb bf 01 00 00 00 d6 38 8c f7 65 8b 05 67 36 3c 76 85 c0 74 02 5b c3 e8 b4 43 3a
RSP: 0018:ffffc9000362fbc0 EFLAGS: 00000282
RAX: 53a44f6fbb7ee500 RBX: ffff8880780b65c0 RCX: 53a44f6fbb7ee500
RDX: dffffc0000000000 RSI: ffffffff8a2b2800 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffff8880780b65c3 R09: 1ffff1100f016cb8
R10: dffffc0000000000 R11: ffffed100f016cb9 R12: ffff8880780b65c0
R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004
spin_unlock_irq include/linux/spinlock.h:414 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
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: 0033:0x7ff2dd212dd7
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007ff2dc8740e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007ff2dd48bfa8 RCX: 00007ff2dd212dd9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff2dd48bfa8
RBP: 00007ff2dd48bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff2dd48c038 R14: 00007ffdcc9c7020 R15: 00007ffdcc9c7108
NMI backtrace for cpu 0
CPU: 0 PID: 4381 Comm: syz.1.18 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:__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: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be 59 97 f7 48 89 df e8 f6 31 98 f7 e8 01 27 b9 f7 fb bf 01 00 00 00 d6 38 8c f7 65 8b 05 67 36 3c 76 85 c0 74 02 5b c3 e8 b4 43 3a
RSP: 0018:ffffc9000363fbc0 EFLAGS: 00000282
RAX: 1c602281a0ff3b00 RBX: ffff8880780b5c80 RCX: 1c602281a0ff3b00
RDX: dffffc0000000000 RSI: ffffffff8a2b2800 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffff8880780b5c83 R09: 1ffff1100f016b90
R10: dffffc0000000000 R11: ffffed100f016b91 R12: ffff8880780b5c80
R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004
spin_unlock_irq include/linux/spinlock.h:414 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
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: 0033:0x7f8eaec40dd7
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007f8eae2a20e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f8eaeeb9fa8 RCX: 00007f8eaec40dd9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8eaeeb9fa8
RBP: 00007f8eaeeb9fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8eaeeba038 R14: 00007fff46f56b70 R15: 00007fff46f56c58
sched: RT throttling activated