rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=9a8c/1/0x4000000000000000 softirq=26517/26517 fqs=5
rcu: 	(detected by 1, t=10502 jiffies, g=31377, q=475 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8585 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3798 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3821 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3876 [inline]
RIP: 0010:__lock_acquire+0x851/0x1a40 kernel/locking/lockdep.c:5237
Code: 05 04 ea 84 14 0f 83 b2 09 00 00 49 be eb 83 b5 80 46 86 c8 61 48 8b 4c 24 08 4c 0f af f1 49 c1 ee 2d 4a 8b 04 f5 a0 ce a7 97 <4e> 8d 2c f5 a0 ce a7 97 48 85 c0 74 1f 48 83 e8 08 48 85 c0 74 16
RSP: 0018:ffffc90000007c18 EFLAGS: 00000802
RAX: ffffffff946b2848 RBX: ffff88807e6fb108 RCX: d99bee890565ebb9
RDX: 000000003bad91d5 RSI: 00000000b2557f00 RDI: 00000000e89d251c
RBP: ffff88807e6fa540 R08: 0000000041d74dc5 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: d99bee890565ebb9
R13: 0000000000000001 R14: 0000000000065c89 R15: 0000000000000001
FS:  000055555c0fa500(0000) GS:ffff888123de8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f799535de50 CR3: 0000000034b7d000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
 debug_object_activate+0x144/0x4b0 lib/debugobjects.c:873
 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline]
 debug_activate kernel/time/hrtimer.c:528 [inline]
 enqueue_hrtimer+0x75/0x2f0 kernel/time/hrtimer.c:1109
 __run_hrtimer kernel/time/hrtimer.c:2048 [inline]
 __hrtimer_run_queues+0x6ed/0x9c0 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__sanitizer_cov_trace_pc+0x2a/0x70 kernel/kcov.c:235
Code: f3 0f 1e fa 65 8b 05 85 a3 59 12 48 8b 34 24 65 48 8b 15 61 a3 59 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 <e9> 91 d4 b2 09 8b 82 24 17 00 00 85 c0 74 f1 8b 82 f8 16 00 00 83
RSP: 0018:ffffc90002e3fdd0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff88807e6fa540 RCX: ffffffff825d32bf
RDX: ffff88807e6fa540 RSI: ffffffff825d32d9 RDI: ffff88807e6fa540
RBP: ffffffff8c3e1160 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000000a9
R13: 0000000000000000 R14: 0000000000000002 R15: ffff88807e6faed8
 __might_fault+0x79/0x140 mm/memory.c:7290
 _inline_copy_from_user include/linux/uaccess.h:169 [inline]
 _copy_from_user+0x29/0xd0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:222 [inline]
 __do_sys_rt_sigprocmask kernel/signal.c:3341 [inline]
 __se_sys_rt_sigprocmask kernel/signal.c:3328 [inline]
 __x64_sys_rt_sigprocmask+0x185/0x410 kernel/signal.c:3328
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f799533f4e7
Code: 00 00 00 53 48 89 fb 48 8d 3d 95 8b e1 00 e8 80 e9 01 00 41 ba 08 00 00 00 31 d2 48 89 de bf 02 00 00 00 b8 0e 00 00 00 0f 05 <5b> c3 0f 1f 80 00 00 00 00 48 83 ec 08 48 8d 3d 0d f8 0e 00 e8 60
RSP: 002b:00007fffe721c000 EFLAGS: 00000246 ORIG_RAX: 000000000000000e
RAX: ffffffffffffffda RBX: 00007fffe721c010 RCX: 00007f799533f4e7
RDX: 0000000000000000 RSI: 00007fffe721c010 RDI: 0000000000000002
RBP: 0000000000000000 R08: 00007f7996158060 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 000000000002d69a R15: 00007fffe721c1f0
 </TASK>
rcu: rcu_preempt kthread starved for 10492 jiffies! g31377 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:27592 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x125c/0x6730 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7326
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 82 Comm: kworker/u8:5 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x58e/0x16c0 kernel/smp.c:892
Code: 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 c9 95 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 2c 0f 00 00 8b 45 08 31 ff 83 e0 01 41
RSP: 0018:ffffc9000247f878 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fd46fd
RDX: ffff88801e7e8000 RSI: ffffffff81fd46d7 RDI: ffff88801e7e8000
RBP: ffff8880b8443680 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170886d1 R14: 0000000000000001 R15: ffff8880b853c880
FS:  0000000000000000(0000) GS:ffff888123ee8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0dcdbeb580 CR3: 000000000e992000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
 on_each_cpu include/linux/smp.h:72 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
 smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x37a/0x550 kernel/jump_label.c:910
 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate mm/kfence/core.c:911 [inline]
 toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:903
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>