rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=e66c/1/0x4000000000000000 softirq=22637/22648 fqs=3 rcu: (detected by 0, t=10504 jiffies, g=17105, q=757 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6509 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:__asan_memset+0x2f/0x50 mm/kasan/shadow.c:87 Code: 41 56 53 48 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 48 89 d6 ba 01 00 00 00 e8 1e e5 ff ff 84 c0 74 11 4c 89 f7 89 ee 48 89 da 5b <41> 5e 5d e9 f9 c0 7e 09 31 c0 5b 41 5e 5d c3 cc cc cc cc cc 66 66 RSP: 0018:ffffc90000a08cd8 EFLAGS: 00000002 RAX: ffffffff8baa5301 RBX: 1ffff110170e507a RCX: ffffffff8baa53f6 RDX: 0000000000000018 RSI: 0000000000000000 RDI: ffff8880772a7300 RBP: 0000000000000000 R08: ffff8880772a7317 R09: 1ffff1100ee54e62 R10: dffffc0000000000 R11: ffffed100ee54e63 R12: ffff8880772a7300 R13: dffffc0000000000 R14: ffff8880772a7300 R15: ffff8880772a7300 FS: 00007f3773277c80(0000) GS:ffff88812555d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f37734cc286 CR3: 000000007b672000 CR4: 00000000003526f0 Call Trace: rb_link_node include/linux/rbtree.h:91 [inline] rb_add_cached include/linux/rbtree.h:210 [inline] timerqueue_add+0x186/0x200 lib/timerqueue.c:40 __run_hrtimer kernel/time/hrtimer.c:1802 [inline] __hrtimer_run_queues+0x650/0xcc0 kernel/time/hrtimer.c:1849 hrtimer_interrupt+0x42b/0x1010 kernel/time/hrtimer.c:1911 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x460 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872 Code: e9 30 ff ff ff e8 75 f6 0c 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 f1 a3 7a 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 56 dc 0f 0a cc 48 8d 3d 2e 6b 73 RSP: 0018:ffffc900039d7518 EFLAGS: 00000286 RAX: 6bcdf2c3fd45d100 RBX: 0000000000000246 RCX: 0000000000000046 RDX: 000000006201c5bd RSI: ffffffff8e168279 RDI: ffffffff8c27c200 RBP: 0000000000000000 R08: ffffffff81767e95 R09: ffffffff8e75e520 R10: ffffc900039d7678 R11: ffffffff81b0c260 R12: 0000000000000002 R13: ffffffff8e75e520 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4873 alloc_filename fs/namei.c:142 [inline] do_getname_kernel+0x54/0x230 fs/namei.c:261 getname_kernel fs/namei.c:284 [inline] class_filename_kernel_constructor include/linux/fs.h:2540 [inline] kern_path+0x25/0x150 fs/namei.c:3039 tomoyo_realpath_nofollow+0x93/0x110 security/tomoyo/realpath.c:303 tomoyo_find_next_domain+0x259/0x1aa0 security/tomoyo/domain.c:731 tomoyo_bprm_check_security+0x11b/0x180 security/tomoyo/tomoyo.c:102 security_bprm_check+0x85/0x240 security/security.c:794 search_binary_handler fs/exec.c:1654 [inline] exec_binprm fs/exec.c:1696 [inline] bprm_execve+0x896/0x1460 fs/exec.c:1748 do_execveat_common+0x50d/0x690 fs/exec.c:1846 __do_sys_execve fs/exec.c:1930 [inline] __se_sys_execve fs/exec.c:1924 [inline] __x64_sys_execve+0x97/0xc0 fs/exec.c:1924 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3773412107 Code: 0f 00 64 c7 00 07 00 00 00 b8 ff ff ff ff c9 c3 0f 1f 00 48 8b 05 a9 ee 0f 00 48 8b 10 e9 01 00 00 00 90 b8 3b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c1 ec 0f 00 f7 d8 64 89 01 48 RSP: 002b:00007fffb21ad548 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 000055ceb38ed1a8 RCX: 00007f3773412107 RDX: 000055ceb38e8e28 RSI: 000055ceb38ed1a8 RDI: 000055ceb38e8eb0 RBP: 000055ceb38e8eb0 R08: 00007fffb21b1e98 R09: 0000000000000210 R10: 0000000000000002 R11: 0000000000000246 R12: 000055ceb38e8e28 R13: 00007f37735d7e8b R14: 000055ceb38e8e28 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10485 jiffies! g17105 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:27656 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 1005 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xce5/0x12c0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b4 e6 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 5f e2 0b 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 43 e2 RSP: 0018:ffffc9000517f700 EFLAGS: 00000293 RAX: ffffffff81b9bebd RBX: 1ffff110170e812d RCX: ffff888027879e80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000517f840 R08: ffffffff9011a3b7 R09: 1ffffffff2023476 R10: dffffc0000000000 R11: fffffbfff2023477 R12: ffff8880b8740968 R13: dffffc0000000000 R14: ffff8880b863bf80 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812545d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f477c19ee9c CR3: 000000000e54c000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2761 [inline] smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2971 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xab/0x290 mm/kfence/core.c:900 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245