rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=9194/1/0x4000000000000000 softirq=89661/89662 fqs=5
rcu: 	(detected by 0, t=10502 jiffies, g=137189, q=576 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 20341 Comm: syz.1.4396 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x64/0x120 kernel/locking/spinlock.c:194
Code: 8b 8c 48 c7 44 24 10 10 7b 95 8a 49 89 e7 49 c1 ef 03 48 b8 f1 f1 f1 f1 f8 f3 f3 f3 49 bc 00 00 00 00 00 fc ff df 4b 89 04 27 <48> 83 c7 18 48 8b 75 08 e8 0f 0a d3 f6 4c 89 f7 e8 b7 dd d3 f6 f7
RSP: 0018:ffffc900001f0c20 EFLAGS: 00000806
RAX: f3f3f3f8f1f1f1f1 RBX: 0000000000000806 RCX: 0000000000000001
RDX: ffffffff974f27d8 RSI: 0000000000000806 RDI: ffffffff974f27d0
RBP: ffffc900001f0cb0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003e174 R12: dffffc0000000000
R13: ffff888060a6ece8 R14: ffffffff974f27d0 R15: 1ffff9200003e184
FS:  00007f74d50d16c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd59830b0a0 CR3: 000000005f2ae000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 debug_object_activate+0x307/0x500 lib/debugobjects.c:765
 debug_hrtimer_activate kernel/time/hrtimer.c:450 [inline]
 debug_activate kernel/time/hrtimer.c:504 [inline]
 enqueue_hrtimer+0x34/0x380 kernel/time/hrtimer.c:1100
 __run_hrtimer kernel/time/hrtimer.c:1771 [inline]
 __hrtimer_run_queues+0x62f/0xc10 kernel/time/hrtimer.c:1818
 hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900039574e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: f3f177daf889aa00
RDX: 0000000000000000 RSI: ffffffff8acadce0 RDI: ffffffff8b1cfa20
RBP: ffffc900039575e8 R08: dffffc0000000000 R09: 1ffffffff223ceb5
R10: dffffc0000000000 R11: fffffbfff223ceb6 R12: 1ffff9200072aea8
R13: ffff888025af6d98 R14: 0000000000000246 R15: dffffc0000000000
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747
 __unix_dgram_recvmsg+0x1fd/0xd90 net/unix/af_unix.c:2409
 sock_recvmsg_nosec net/socket.c:1047 [inline]
 sock_recvmsg net/socket.c:1069 [inline]
 ____sys_recvmsg+0x2bd/0x5d0 net/socket.c:2814
 ___sys_recvmsg+0x214/0x590 net/socket.c:2856
 do_recvmmsg+0x377/0x810 net/socket.c:2950
 __sys_recvmmsg net/socket.c:3029 [inline]
 __do_sys_recvmmsg net/socket.c:3052 [inline]
 __se_sys_recvmmsg net/socket.c:3045 [inline]
 __x64_sys_recvmmsg+0x199/0x250 net/socket.c:3045
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f74d419de59
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:00007f74d50d1028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f74d4426090 RCX: 00007f74d419de59
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007f74d4233e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f74d4426128 R14: 00007f74d4426090 R15: 00007ffe1e031728
 </TASK>
rcu: rcu_preempt kthread starved for 10492 jiffies! g137189 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:27848 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 8789 Comm: kworker/u4:24 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:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xd85/0x1190 kernel/smp.c:855
Code: 45 8b 34 24 44 89 f6 83 e6 01 31 ff e8 54 f1 0a 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 8f ed 0a 00 eb 38 f3 90 <42> 0f b6 04 33 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 73 ed
RSP: 0018:ffffc9000c3d7780 EFLAGS: 00000293
RAX: ffffffff817bf7fd RBX: 1ffff110171e82bd RCX: ffff8880214e8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000c3d7900 R08: ffffffff911e7507 R09: 1ffffffff223cea0
R10: dffffc0000000000 R11: fffffbfff223cea1 R12: ffff8880b8f415e8
R13: ffff8880b8e3d3c0 R14: dffffc0000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd5982cb000 CR3: 000000000cf32000 CR4: 00000000003506f0
DR0: 00000000ea2b0e2c DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
 text_poke_bp_batch+0x31e/0x980 arch/x86/kernel/alternative.c:2432
 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
 static_key_enable+0x1a/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xa8/0x260 mm/kfence/core.c:847
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>