rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=03b4/1/0x4000000000000000 softirq=21658/21659 fqs=9
(detected by 1, t=10506 jiffies, g=27385, q=285 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6791 Comm: syz.3.631 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4746 [inline]
RIP: 0010:__lock_acquire+0x8d3/0x7d10 kernel/locking/lockdep.c:4999
Code: 0f 85 55 62 00 00 48 8b 44 24 40 44 3b 30 0f 8d 7e 02 00 00 49 63 de 48 8d 04 9b 4d 8d a4 c7 00 0b 00 00 48 c7 c0 40 61 c0 96 <48> c1 e8 03 48 89 84 24 90 00 00 00 48 c7 c0 a8 5e 20 8e 48 c1 e8
RSP: 0018:ffffc90000007860 EFLAGS: 00000097
RAX: ffffffff96c06140 RBX: 0000000000000001 RCX: ffff88802a6d9e00
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90aff240
RBP: ffffc90000007ab0 R08: dffffc0000000000 R09: 1ffffffff215fe48
R10: dffffc0000000000 R11: fffffbfff215fe49 R12: ffff88802a6da928
R13: ffff88802a6da902 R14: 0000000000000001 R15: ffff88802a6d9e00
FS: 00007f9a66dd56c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a66dd4ff8 CR3: 0000000078d30000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
debug_object_activate+0x68/0x4f0 lib/debugobjects.c:698
debug_hrtimer_activate kernel/time/hrtimer.c:448 [inline]
debug_activate kernel/time/hrtimer.c:502 [inline]
enqueue_hrtimer+0x37/0x410 kernel/time/hrtimer.c:1097
__run_hrtimer kernel/time/hrtimer.c:1768 [inline]
__hrtimer_run_queues+0x687/0xd50 kernel/time/hrtimer.c:1815
hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1877
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
__sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:ns_of_pid include/linux/pid.h:156 [inline]
RIP: 0010:task_active_pid_ns kernel/pid.c:509 [inline]
RIP: 0010:pid_vnr+0x5d/0x1d0 kernel/pid.c:488
Code: 80 3c 20 00 74 08 4c 89 f7 e8 df 5f 7d 00 4d 8b 36 4d 85 f6 0f 84 9c 00 00 00 49 8d 7e 04 48 89 f8 48 c1 e8 03 42 0f b6 04 20 <84> c0 0f 85 f0 00 00 00 41 8b 46 04 48 c1 e0 04 4d 8d b4 06 d8 00
RSP: 0018:ffffc90003fdf708 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc90010f29000 RSI: 000000000007ffff RDI: ffff8880573293c4
RBP: ffffc90003fdf8d0 R08: ffff8880271a5067 R09: 1ffff11004e34a0c
R10: dffffc0000000000 R11: ffffed1004e34a0d R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff8880573293c0 R15: ffff888056446b40
scm_set_cred include/net/scm.h:71 [inline]
__unix_dgram_recvmsg+0x82c/0xdc0 net/unix/af_unix.c:2499
____sys_recvmsg+0x2cb/0x5e0 net/socket.c:-1
___sys_recvmsg+0x212/0x590 net/socket.c:2779
do_recvmmsg+0x393/0x870 net/socket.c:2873
__sys_recvmmsg net/socket.c:2952 [inline]
__do_sys_recvmmsg net/socket.c:2975 [inline]
__se_sys_recvmmsg net/socket.c:2968 [inline]
__x64_sys_recvmmsg+0x195/0x250 net/socket.c:2968
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9a68b9ce59
Code: 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 01 48
RSP: 002b:00007f9a66dd5028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f9a68e16180 RCX: 00007f9a68b9ce59
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007f9a68c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9a68e16218 R14: 00007f9a68e16180 R15: 00007fffa2067f18
</TASK>
rcu: rcu_preempt kthread starved for 10435 jiffies! g27385 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:27184 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 75 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline]
RIP: 0010:smp_call_function_many_cond+0xea2/0x1290 kernel/smp.c:998
Code: 00 00 00 41 8b 1f 89 de 83 e6 01 31 ff e8 f6 f6 0a 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 82 f3 0a 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 67 f3 0a
RSP: 0018:ffffc90001597800 EFLAGS: 00000293
RAX: ffffffff81778839 RBX: dffffc0000000000 RCX: ffff888018f9da00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90001597960 R08: ffffffff90aff247 R09: 1ffffffff215fe48
R10: dffffc0000000000 R11: fffffbfff215fe49 R12: 1ffff110171c8601
R13: ffff8880b8f3bbc0 R14: 0000000000000000 R15: ffff8880b8e43008
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30119ff8 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
text_poke_bp_batch+0x2b7/0x850 arch/x86/kernel/alternative.c:1774
text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
static_key_enable+0x16/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821
process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
vkms_vblank_simulate: vblank timer overrun