rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=c524/1/0x4000000000000000 softirq=18167/18168 fqs=2 rcu: (detected by 1, t=10506 jiffies, g=9121, q=417 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5859 Comm: udevd Not tainted 6.16.0-rc7-syzkaller-00114-g327579671a9b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:lock_release+0x16b/0x2f0 kernel/locking/lockdep.c:5895 Code: 0f 84 00 01 00 00 48 c7 c7 d5 b1 e0 8d e8 ad 10 ee 09 b8 ff ff ff ff 65 0f c1 05 28 bd 37 12 83 f8 01 0f 85 1d 01 00 00 9c 58 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 RSP: 0018:ffffc90000007cc0 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffffffff9afd7e28 RCX: ffffc90000007ccc RDX: 0000000000000004 RSI: ffffffff8de0b1d5 RDI: ffffffff8c1574e0 RBP: 0000000000000006 R08: 0000000000000001 R09: fffff52000000f92 R10: 0000000000000006 R11: ffffffff9afd7e10 R12: ffffffff84e0971c R13: 0000000000000006 R14: ffff888035550000 R15: 0000000000000005 FS: 00007f217c01f880(0000) GS:ffff888124720000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff5df5b7bac CR3: 0000000064804000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x1a/0x80 kernel/locking/spinlock.c:194 debug_object_activate+0x2ec/0x4c0 lib/debugobjects.c:836 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x23/0x3b0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x8ff/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5875 Code: 76 37 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 12 b8 10 0f 0f 82 74 02 00 00 8b 35 fa e9 10 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 a9 75 37 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc90003fcf6b0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e785620 RCX: ffffffff93dd5960 RDX: 0000000000000000 RSI: ffffffff8de0b1d5 RDI: ffffffff8c1574e0 RBP: 0000000000000000 R08: 4c661a134e2ac631 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 fs_reclaim_acquire mm/page_alloc.c:4062 [inline] fs_reclaim_acquire+0xca/0x150 mm/page_alloc.c:4053 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4099 [inline] slab_alloc_node mm/slub.c:4177 [inline] kmem_cache_alloc_noprof+0x53/0x3b0 mm/slub.c:4204 lsm_inode_alloc security/security.c:755 [inline] security_inode_alloc+0x3b/0x2b0 security/security.c:1697 inode_init_always_gfp+0xce4/0x1030 fs/inode.c:306 inode_init_always include/linux/fs.h:3281 [inline] alloc_inode+0x86/0x240 fs/inode.c:353 new_inode+0x22/0x1c0 fs/inode.c:1145 __shmem_get_inode mm/shmem.c:3049 [inline] shmem_get_inode+0x19a/0xfb0 mm/shmem.c:3123 shmem_mknod+0x1a8/0x450 mm/shmem.c:3844 lookup_open.isra.0+0x11d3/0x1580 fs/namei.c:3717 open_last_lookups fs/namei.c:3816 [inline] path_openat+0x893/0x2cb0 fs/namei.c:4052 do_filp_open+0x20b/0x470 fs/namei.c:4082 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f217b8a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007fffe3e60b90 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f217c01f880 RCX: 00007f217b8a7407 RDX: 0000000000080241 RSI: 00007fffe3e610f0 RDI: ffffffffffffff9c RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000001b6 R11: 0000000000000202 R12: 00005604f504bdfc R13: 00005604f504bdfc R14: 0000000000000001 R15: 00005604f5066140 rcu: rcu_preempt kthread starved for 10495 jiffies! g9121 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:28872 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5dd0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6879 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 1158 Comm: kworker/u8:7 Not tainted 6.16.0-rc7-syzkaller-00114-g327579671a9b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:write_comp_data+0x8b/0x90 kernel/kcov.c:272 Code: 00 00 4a 8d 34 dd 28 00 00 00 48 39 f2 72 1b 48 83 c7 01 48 89 38 4c 89 44 30 e0 4c 89 4c 30 e8 4c 89 54 30 f0 4a 89 4c d8 20 c0 90 cd 09 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 RSP: 0018:ffffc9000436f898 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b84421e0 RCX: ffffffff81afd3ed RDX: ffff888028930000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed101708843d R15: ffff8880b853b580 FS: 0000000000000000(0000) GS:ffff888124820000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560521c4bd28 CR3: 000000000e382000 CR4: 00000000003526f0 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0xd9d/0x1510 kernel/smp.c:885 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2691 [inline] smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2901 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:850 [inline] toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245