rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=2d64/1/0x4000000000000000 softirq=42700/42701 fqs=1 rcu: (detected by 0, t=10506 jiffies, g=46453, q=137 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 8637 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline] RIP: 0010:lock_is_held_type+0x5a/0x150 kernel/locking/lockdep.c:5939 Code: 4c 8b 2d 81 48 90 07 41 83 bd 8c 0b 00 00 00 0f 85 bf 00 00 00 89 f5 49 89 fe 9c 41 5c fa 48 c7 c7 f2 5f fc 8d e8 e6 19 00 00 <65> ff 05 ff 8d 90 07 41 83 bd 88 0b 00 00 00 7e 48 4c 89 eb 48 81 RSP: 0018:ffffc90000a08cd8 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 00000000ffffffff RCX: 0000000000010001 RDX: ffff88802c813d80 RSI: ffffffff8dfc5ff2 RDI: ffffffff8c28b660 RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000141190 R12: 0000000000000046 R13: ffff88802c813d80 R14: ffff8880309412c0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125389000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff3f74adc0 CR3: 0000000058684000 CR4: 0000000000350ef0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0x14c/0xc20 net/sched/sch_taprio.c:933 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 f1 6d 07 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 db b8 97 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ab 89 6e ff cc 48 8d 3d 88 73 92 RSP: 0018:ffffc900037d7248 EFLAGS: 00000286 RAX: 03a69ebbd4c65500 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000a42637f2 RSI: ffffffff8e21f706 RDI: ffffffff8c28b660 RBP: ffffffff8470eb24 R08: ffffffff8470eb24 R09: ffffffff8e95cca0 R10: dffffc0000000000 R11: fffffbfff206199f R12: 0000000000000002 R13: ffffffff8e95cca0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] setid_policy_lookup+0x40/0x560 security/safesetid/lsm.c:72 safesetid_security_capable+0x8c/0x1a0 security/safesetid/lsm.c:114 security_capable+0xcd/0x2c0 security/security.c:660 has_ns_capability_noaudit+0x136/0x250 kernel/capability.c:307 ima_match_rules security/integrity/ima/ima_policy.c:621 [inline] ima_match_policy+0xaa8/0x21e0 security/integrity/ima/ima_policy.c:772 ima_get_action+0x75/0xb0 security/integrity/ima/ima_api.c:201 process_measurement+0x2ec/0x1c80 security/integrity/ima/ima_main.c:283 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685 security_file_post_open+0xb3/0x260 security/security.c:2755 do_open fs/namei.c:4701 [inline] path_openat+0x2e4d/0x3860 fs/namei.c:4858 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f15b9dc70ba Code: 41 89 f2 48 89 54 24 e0 41 83 e2 40 75 2a 89 f0 f7 d0 a9 00 00 41 00 74 1f 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 2e c3 0f 1f 44 00 00 48 8d 44 24 08 c7 44 24 RSP: 002b:00007fff3f74a5e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fff3f74a660 RCX: 00007f15b9dc70ba RDX: 0000000000080000 RSI: 00007fff3f74a660 RDI: 00000000ffffff9c RBP: 00007fff3f74a650 R08: 00007fff3f74a857 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000001c R13: 00007f15b9d9b000 R14: 00007fff3f74a870 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10500 jiffies! g46453 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 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+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 49 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) 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:342 [inline] RIP: 0010:smp_call_function_many_cond+0xfd4/0x13d0 kernel/smp.c:892 Code: 89 ee 83 e6 01 31 ff e8 7a 06 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 25 02 0c 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 0a 02 0c 00 eb e5 44 89 RSP: 0018:ffffc90000b97700 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b863c148 RCX: ffff8880226d8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000b97840 R08: ffffffff9030ccf7 R09: 1ffffffff206199e R10: dffffc0000000000 R11: fffffbfff206199f R12: 1ffff110170e8169 R13: dffffc0000000000 R14: ffff8880b8740b48 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125289000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb7ca022fd0 CR3: 000000000e74a000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 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+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983 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:906 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245