rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 ticks this GP) idle=17ec/1/0x4000000000000000 softirq=41698/41698 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9210/1:b..l rcu: (detected by 0, t=10505 jiffies, g=40337, q=206 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5342 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: events_freezable_pwr_efficient sync_hw_clock RIP: 0010:get_current arch/x86/include/asm/current.h:23 [inline] RIP: 0010:write_comp_data+0x10/0x90 kernel/kcov.c:245 Code: 6d fd ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 8b 05 99 25 5a 12 49 89 f8 49 89 f1 49 89 d2 <65> 48 8b 3d 70 25 5a 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 RSP: 0018:ffffc90000a08e90 EFLAGS: 00000046 RAX: 0000000080010000 RBX: dffffc0000000000 RCX: ffffffff81f61124 RDX: 0000000000000001 RSI: 0000000000000007 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000007 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888059c91300 R13: 0000000000000001 R14: ffff8880b8528540 R15: ffff8880b8528590 FS: 0000000000000000(0000) GS:ffff888123ed8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33123ffc CR3: 000000007baca000 CR4: 00000000003526f0 Call Trace: cpu_max_bits_warn include/linux/cpumask.h:140 [inline] cpumask_check include/linux/cpumask.h:147 [inline] cpumask_test_cpu include/linux/cpumask.h:651 [inline] cpu_online include/linux/cpumask.h:1233 [inline] trace_hrtimer_expire_exit include/trace/events/timer.h:321 [inline] __run_hrtimer kernel/time/hrtimer.c:2035 [inline] __hrtimer_run_queues+0x164/0x9c0 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 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 3b 8d 7e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 c6 93 3c 0f 0f 82 ac 02 00 00 8b 35 8e c7 3c 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd 8c 7e 12 0f 85 ec 02 00 00 48 83 c4 RSP: 0018:ffffc9000301fbd0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8e18229c RDI: ffffffff8c402680 RBP: ffff88801bc0d940 R08: 00000000ffffffff R09: 0000000000000e04 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 process_one_work+0x1307/0x1940 kernel/workqueue.c:3297 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:syz.1.882 state:R running task stack:28568 pid:9210 tgid:9209 ppid:5612 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:get_current arch/x86/include/asm/current.h:23 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xf/0x70 kernel/kcov.c:216 Code: 00 00 00 5b e9 02 32 13 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 8b 05 45 1e 5a 12 48 8b 34 24 <65> 48 8b 15 21 1e 5a 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 RSP: 0018:ffffc9000605f840 EFLAGS: 00000202 RAX: 0000000080000000 RBX: 00000000000000d8 RCX: ffffc90006821000 RDX: 0000000000080000 RSI: ffffffff84d94cbe RDI: ffff8880321e8000 RBP: 0000000000000000 R08: 0000000000000005 R09: 000000000000017f R10: 00000000000000d8 R11: 0000000000000000 R12: ffff888026a00c68 R13: ffff888026a00d20 R14: ffffc9000605fc00 R15: dffffc0000000000 context_struct_compute_av+0xbfe/0x1250 security/selinux/ss/services.c:658 security_compute_av+0x5ea/0x11e0 security/selinux/ss/services.c:1178 avc_compute_av+0x84/0x820 security/selinux/avc.c:992 avc_perm_nonode+0xb1/0x180 security/selinux/avc.c:1117 avc_has_perm_noaudit+0x2d4/0x3b0 security/selinux/avc.c:1160 avc_has_perm+0xbd/0x1e0 security/selinux/avc.c:1195 may_create+0x37a/0x440 security/selinux/hooks.c:1880 security_inode_mkdir+0xe5/0x280 security/security.c:1716 vfs_mkdir+0x245/0x850 fs/namei.c:5264 filename_mkdirat+0x48b/0x5e0 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat fs/namei.c:5327 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327 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: 0033:0x7f5c6cb9e019 RSP: 002b:00007f5c6d991028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f5c6ce25fa0 RCX: 00007f5c6cb9e019 RDX: 0000000000000000 RSI: 0000200000002000 RDI: ffffffffffffff9c RBP: 00007f5c6cc3500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5c6ce26038 R14: 00007f5c6ce25fa0 R15: 00007ffdf6c87058 rcu: rcu_preempt kthread starved for 10500 jiffies! g40337 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:29168 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: 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 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 1127 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x58e/0x1870 kernel/smp.c:912 Code: b8 00 00 00 00 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 44 9a 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 a8 10 00 00 8b 45 08 31 RSP: 0018:ffffc9000579f858 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fdc7c2 RDX: ffff88802a058000 RSI: ffffffff81fdc79c RDI: ffff88802a058000 RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880 FS: 0000000000000000(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33718ff8 CR3: 000000000e994000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1077 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