rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18581/1:b..l
(detected by 0, t=10502 jiffies, g=96213, q=68)
task:syz.5.4568 state:R running task stack:25760 pid:18581 ppid: 15204 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
__wake_up_common_lock kernel/sched/wait.c:140 [inline]
__wake_up_sync_key+0x11b/0x180 kernel/sched/wait.c:205
sock_def_readable+0x136/0x250 net/core/sock.c:3098
__netlink_sendskb net/netlink/af_netlink.c:1264 [inline]
netlink_broadcast_deliver net/netlink/af_netlink.c:1401 [inline]
do_one_broadcast net/netlink/af_netlink.c:1488 [inline]
netlink_broadcast_filtered+0xcbc/0x1170 net/netlink/af_netlink.c:1532
netlink_broadcast+0x33/0x40 net/netlink/af_netlink.c:1556
uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
kobject_uevent_net_broadcast+0x364/0x530 lib/kobject_uevent.c:409
kobject_uevent_env+0x556/0x890 lib/kobject_uevent.c:608
kvm_uevent_notify_change+0x2fb/0x3a0 virt/kvm/kvm_main.c:5498
kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:4787 [inline]
kvm_dev_ioctl+0x17d6/0x2040 virt/kvm/kvm_main.c:4809
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
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: 0033:0x7f390ec8dec9
RSP: 002b:00007f390cef5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f390eee4fa0 RCX: 00007f390ec8dec9
RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000004
RBP: 00007f390ed10f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f390eee5038 R14: 00007f390eee4fa0 R15: 00007ffd201f9148
rcu: rcu_preempt kthread starved for 10522 jiffies! g96213 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:27464 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:
NMI backtrace for cpu 0
CPU: 0 PID: 18586 Comm: syz.4.4569 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_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: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:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc900030afb60 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 53c52cf0b3a32a00
RDX: 0000000000000000 RSI: ffffffff8a0b2ac0 RDI: ffffffff8a59a4c0
RBP: ffffc900030afc80 R08: dffffc0000000000 R09: fffffbfff1ff7a1f
R10: fffffbfff1ff7a1f R11: 1ffffffff1ff7a1e R12: ffff888027a75c28
R13: 1ffff92000615f78 R14: 0000000000000246 R15: dffffc0000000000
__might_fault+0xb3/0x110 mm/memory.c:5357
_copy_from_user+0x29/0x170 lib/usercopy.c:14
copy_from_user include/linux/uaccess.h:192 [inline]
restore_sigcontext arch/x86/kernel/signal.c:91 [inline]
__ia32_sys_rt_sigreturn+0x1e6/0x790 arch/x86/kernel/signal.c:674
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: 0033:0x7efc03115f79
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:00007efc013e0b40 EFLAGS: 00000206 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007efc033d0fa8 RCX: 00007efc03115f79
RDX: 00007efc013e0b40 RSI: 00007efc013e0c70 RDI: 0000000000000021
RBP: 00007efc033d0fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007efc033d1038 R14: 00007fff3f352e00 R15: 00007fff3f352ee8