rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5193/2:b..l
rcu: (detected by 1, t=10502 jiffies, g=45357, q=755 ncpus=2)
task:udevd state:R running task stack:24368 pid:5193 tgid:5193 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x74/0x80 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
unlock_task_sighand include/linux/sched/signal.h:756 [inline]
do_send_sig_info kernel/signal.c:1270 [inline]
group_send_sig_info+0x233/0x260 kernel/signal.c:1419
kill_pid_info_type+0xf8/0x1f0 kernel/signal.c:1459
kill_pid_info kernel/signal.c:1473 [inline]
kill_proc_info+0xd9/0x180 kernel/signal.c:1480
kill_something_info kernel/signal.c:1577 [inline]
__do_sys_kill kernel/signal.c:3953 [inline]
__se_sys_kill+0xc4/0x450 kernel/signal.c:3947
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb61325f357
RSP: 002b:00007ffffa6d6db8 EFLAGS: 00000297 ORIG_RAX: 000000000000003e
RAX: ffffffffffffffda RBX: 00007ffffa6d6dc0 RCX: 00007fb61325f357
RDX: 000055f38480c550 RSI: 000000000000000f RDI: 00000000000025fd
RBP: 0000000000000000 R08: 0000000000000010 R09: 000055f3847b78e0
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000
R13: 000055f345029100 R14: 0000000000000000 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10517 jiffies! g45357 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:27792 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10337 Comm: syz.3.742 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:preempt_count_add+0x13/0x190 kernel/sched/core.c:5719
Code: 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 49 bf 00 00 00 00 00 fc ff df <48> c7 c0 20 54 8b 99 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 eb 00
RSP: 0018:ffffc90000007bb8 EFLAGS: 00000096
RAX: b338031c9fd1dd00 RBX: ffff8880593e9e80 RCX: ffffffff81870d04
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffff8880593e9e80 R08: ffff8880593e9e87 R09: 1ffff1100b27d3d0
R10: dffffc0000000000 R11: ffffed100b27d3d1 R12: dffffc0000000000
R13: ffff8880306ecc00 R14: 0000000000000000 R15: dffffc0000000000
FS: 00007f9ef358a6c0(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fca75ae8d58 CR3: 000000007b493000 CR4: 0000000000350ef0
Call Trace:
<IRQ>
class_preempt_constructor include/linux/preempt.h:468 [inline]
try_to_wake_up+0x3c/0x12b0 kernel/sched/core.c:4070
signal_wake_up_state+0xb5/0x120 kernel/signal.c:734
posixtimer_send_sigqueue+0x404/0xa70 kernel/signal.c:2080
posix_timer_queue_signal kernel/time/posix-timers.c:364 [inline]
posix_timer_fn+0x121/0x1c0 kernel/time/posix-timers.c:379
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:do_sigaltstack include/linux/sched/signal.h:-1 [inline]
RIP: 0010:restore_altstack+0x1f8/0x4b0 kernel/signal.c:4463
Code: 89 df 4c 89 fe e8 e8 8e 38 00 4c 39 fb 0f 86 72 02 00 00 e8 7a 8c 38 00 eb 0c e8 73 8c 38 00 eb 09 e8 6c 8c 38 00 4c 8b 3c 24 <44> 8b 6c 24 0c 41 81 e5 ff ff ff 7f bf 03 00 00 00 44 89 ee e8 8f
RSP: 0018:ffffc90005327ba0 EFLAGS: 00000293
RAX: ffffffff81886c36 RBX: 00007f9ef3589b40 RCX: ffff8880593e9e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f9ef3589b40
RBP: ffffc90005327c90 R08: ffffc90005327c17 R09: 1ffff92000a64f82
R10: dffffc0000000000 R11: fffff52000a64f83 R12: 1ffff92000a64f7c
R13: ffff8880593ea828 R14: 0000000000000002 R15: ffff8880593e9e80
__ia32_sys_rt_sigreturn+0x281/0x860 arch/x86/kernel/signal_64.c:265
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9ef272b829
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 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 04 25
RSP: 002b:00007f9ef3589b40 EFLAGS: 00000206 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f9ef29e6098 RCX: 00007f9ef272b829
RDX: 00007f9ef3589b40 RSI: 00007f9ef3589c70 RDI: 0000000000000021
RBP: 00007f9ef29e6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f9ef29e6128 R14: 00007ffd0e6a6570 R15: 00007ffd0e6a6658
</TASK>