rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3560/1:b..l
(detected by 1, t=10502 jiffies, g=37277, q=85)
task:udevd state:R running task stack:23168 pid: 3560 ppid: 1 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6552
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6577
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:403 [inline]
lockref_put_or_lock+0x6e/0xb0 lib/lockref.c:177
fast_dput+0x154/0x280 fs/dcache.c:754
dput+0xb7/0x1a0 fs/dcache.c:880
open_last_lookups fs/namei.c:3547 [inline]
path_openat+0x28ef/0x2f30 fs/namei.c:3739
do_filp_open+0x1b3/0x3e0 fs/namei.c:3769
do_sys_openat2+0x142/0x4a0 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1280
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: 0033:0x7f35d0935407
RSP: 002b:00007ffef139e7e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f35d0847880 RCX: 00007f35d0935407
RDX: 0000000000080141 RSI: 0000561fdc1a802e RDI: ffffffffffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001a4 R11: 0000000000000202 R12: 00000000ffffffff
R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10527 jiffies! g37277 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:28032 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
schedule+0x11b/0x1e0 kernel/sched/core.c:6459
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:
NMI backtrace for cpu 1
CPU: 1 PID: 10590 Comm: syz.7.1513 Not tainted 5.15.188-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 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:1690 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
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:__local_bh_disable_ip+0xa/0x190 kernel/softirq.c:323
Code: 89 f6 89 c9 e9 57 0f 39 00 0f 1f 80 00 00 00 00 89 f6 e9 a9 09 39 00 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 41 54 <53> 48 83 e4 e0 48 81 ec 80 00 00 00 89 f3 65 48 8b 04 25 28 00 00
RSP: 0018:ffffc90003f9faf8 EFLAGS: 00000246
RAX: ffffffff812bdd3a RBX: 00007fbaf88e7d00 RCX: 0000000000080000
RDX: ffffc90011e66000 RSI: 0000000000000200 RDI: ffffffff812bdd35
RBP: ffffc90003f9fb10 R08: dffffc0000000000 R09: ffffed100f57366a
R10: ffffed100f57366a R11: 1ffff1100f573669 R12: dffffc0000000000
R13: 1ffff1100f5736a9 R14: 1ffff1100f5733b8 R15: ffff88807ab99dc0
fpregs_lock arch/x86/include/asm/fpu/api.h:70 [inline]
copy_fpstate_to_sigframe+0x1fc/0xb90 arch/x86/kernel/fpu/signal.c:198
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+0xb1/0x140 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: 0033:0x7fbafaa80929
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:00007fbaf88e80e8 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00007fbafaca7fa8 RCX: 00007fbafaa80929
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbafaca7fa8
RBP: 00007fbafaca7fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbafaca7fac
R13: 0000000000000000 R14: 00007ffd322eed10 R15: 00007ffd322eedf8