rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=e74c/0/0x1 softirq=27143/27143 fqs=20
rcu: 	(detected by 1, t=10505 jiffies, g=18081, q=815 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc5-syzkaller-00136-g4d64321c4f6f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__lock_acquire+0x821/0xd20 kernel/locking/lockdep.c:-1
Code: c4 4c 89 f1 48 c1 e9 20 89 ca c1 c2 04 41 29 cc 44 31 e2 44 01 f1 41 29 d6 89 d6 c1 c6 06 44 31 f6 01 ca 89 f0 c1 c0 08 29 f1 <31> c8 01 d6 29 c2 89 c1 c1 c1 10 31 d1 01 f0 41 89 cd 41 c1 c5 13
RSP: 0018:ffffc90000007b80 EFLAGS: 00000002
RAX: 00000000ffe30dff RBX: 0000000000000000 RCX: 0000000000001cf1
RDX: 00000000ffffff8b RSI: 00000000ffffe30d RDI: ffffffff8dc95240
RBP: ffffffff8dc95d30 R08: 0000000000000000 R09: 0000000000080000
R10: 0000000000000000 R11: ffffffff81ae3872 R12: 0000000000000072
R13: 0000000000000000 R14: 0000000000000072 R15: ffffffff8dc95d30
FS:  0000000000000000(0000) GS:ffff8881260cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a91ece3898 CR3: 0000000032058000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
 _raw_spin_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:170
 __run_hrtimer kernel/time/hrtimer.c:1765 [inline]
 __hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 fb 11 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: 6ff2bb85aec9d500 RBX: ffffffff81974f28 RCX: 6ff2bb85aec9d500
RDX: 0000000000000001 RSI: ffffffff8d74ac7a RDI: ffffffff8bc1d260
RBP: ffffffff8dc07ec0 R08: ffff8880b8832b5b R09: 1ffff1101710656b
R10: dffffc0000000000 R11: ffffed101710656c R12: ffffffff8f7ed270
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a48
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 rest_init+0x2de/0x300 init/main.c:743
 start_kernel+0x470/0x4f0 init/main.c:1099
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513
 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494
 common_startup_64+0x13e/0x147
 </TASK>
rcu: rcu_preempt kthread starved for 10405 jiffies! g18081 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:27496 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 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: 152 Comm: kworker/u8:5 Not tainted 6.15.0-rc5-syzkaller-00136-g4d64321c4f6f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0xe69/0x11c0 kernel/smp.c:885
Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 20 6d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 cb 68 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 b0 68 0b
RSP: 0018:ffffc90002eb7700 EFLAGS: 00000293
RAX: ffffffff81b467a0 RBX: ffff8880b893ad40 RCX: ffff8880203d8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002eb7860 R08: ffffffff8f7ed277 R09: 1ffffffff1efda4e
R10: dffffc0000000000 R11: fffffbfff1efda4f R12: 1ffff11017108245
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8841228
FS:  0000000000000000(0000) GS:ffff8881261cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557fb915c8 CR3: 000000000dd36000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2455 [inline]
 text_poke_bp_batch+0x319/0x940 arch/x86/kernel/alternative.c:2665
 text_poke_flush arch/x86/kernel/alternative.c:2856 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2863
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>