rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=7ed4/1/0x4000000000000002 softirq=81080/81080 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5137/1:b..l rcu: (detected by 1, t=10506 jiffies, g=92801, q=87 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] RIP: 0010:rcu_is_watching+0x35/0xb0 kernel/rcu/tree.c:700 Code: 05 38 cb 92 7e e8 5b 15 16 09 89 c3 83 f8 08 73 60 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 30 9a a7 8c 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 2c 78 6e 00 48 c7 c3 28 6b 03 00 RSP: 0018:ffffc90000007ce8 EFLAGS: 00000802 RAX: 1ffffffff194f346 RBX: 0000000000000000 RCX: a9cf266ef9a48400 RDX: ffffffff8ce93440 RSI: ffffffff8b1c9840 RDI: ffffffff8b1c9800 RBP: 0000000000000001 R08: ffffffff8e8b2fef R09: 1ffffffff1d165fd R10: dffffc0000000000 R11: fffffbfff1d165fe R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff8ca79a30 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb9a0be6ff8 CR3: 000000007ddd7000 CR4: 00000000003506f0 Call Trace: trace_hrtimer_start include/trace/events/timer.h:202 [inline] debug_activate kernel/time/hrtimer.c:506 [inline] enqueue_hrtimer+0x9d/0x370 kernel/time/hrtimer.c:1108 __run_hrtimer kernel/time/hrtimer.c:1767 [inline] __hrtimer_run_queues+0x63a/0xc40 kernel/time/hrtimer.c:1814 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876 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 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255 Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 e9 de 04 00 00 4c 8b 75 d0 4c 89 e7 e8 60 23 33 09 e8 ab 29 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffffff8ce07af8 EFLAGS: 00000282 RAX: a9cf266ef9a48400 RBX: 0000000000000000 RCX: a9cf266ef9a48400 RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9860 RBP: ffffffff8ce07b50 R08: ffffffff8e8b2fef R09: 1ffffffff1d165fd R10: dffffc0000000000 R11: fffffbfff1d165fe R12: ffffffff8ce93440 R13: dffffc0000000000 R14: ffff88802b94da00 R15: ffff8880b8e3cac8 context_switch kernel/sched/core.c:5384 [inline] __schedule+0x155b/0x45a0 kernel/sched/core.c:6700 schedule_idle+0x4e/0x80 kernel/sched/core.c:6802 do_idle+0x539/0x590 kernel/sched/idle.c:331 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:840 start_kernel+0x459/0x4e0 init/main.c:1085 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b task:udevd state:R running task stack:23048 pid:5137 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 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:ffffc900032e7820 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 4b45ef7b91de1d00 RDX: 0000000000000000 RSI: ffffffff8acadd60 RDI: ffffffff8b1c9860 RBP: ffffc900032e7930 R08: dffffc0000000000 R09: 1ffffffff2238ea0 R10: dffffc0000000000 R11: fffffbfff2238ea1 R12: 1ffff9200065cf10 R13: ffffffff8d132160 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] is_bpf_text_address+0x47/0x2a0 kernel/bpf/core.c:741 kernel_text_address+0xa0/0xd0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] kmem_cache_free+0xf8/0x270 mm/slub.c:3852 file_free fs/file_table.c:77 [inline] __fput+0x61c/0x970 fs/file_table.c:397 __do_sys_close fs/open.c:1573 [inline] __se_sys_close+0x15f/0x220 fs/open.c:1558 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: 0033:0x7fee29515a67 RSP: 002b:00007ffd6bc6faf8 EFLAGS: 00000206 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 000055597f54ad50 RCX: 00007fee29515a67 RDX: 000000000000ee61 RSI: 00007fee295f1b20 RDI: 000000000000000e RBP: 000055597f5171c0 R08: 0000000000006e20 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000206 R12: 000055597f5157b0 R13: 00000000000000fe R14: 0000555973254be0 R15: 00007ffd6bc6fdb0 rcu: rcu_preempt kthread starved for 10506 jiffies! g92801 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:26728 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 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+0x313/0x1590 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 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 5984 Comm: kworker/u4:10 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline] RIP: 0010:smp_call_function_many_cond+0xe03/0x1140 kernel/smp.c:855 Code: 89 ee 83 e6 01 31 ff e8 cb f5 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 06 f2 0a 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 ea f1 0a 00 eb e4 44 RSP: 0018:ffffc9000555f780 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110171c8759 RCX: ffff8880241bbc00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000555f900 R08: ffffffff911c7507 R09: 1ffffffff2238ea0 R10: dffffc0000000000 R11: fffffbfff2238ea1 R12: ffff8880b8e43ac8 R13: dffffc0000000000 R14: ffff8880b8f3d148 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f883354da08 CR3: 000000000cf32000 CR4: 00000000003506e0 Call Trace: 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/0x990 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+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 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