rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (2 ticks this GP) idle=2294/1/0x4000000000000000 softirq=17803/17803 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=9753, q=2690 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5236 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] RIP: 0010:do_raw_spin_lock+0x6d/0x290 kernel/locking/spinlock_debug.c:115 Code: 28 2a 0e b0 8d 48 c7 44 24 30 c0 fe 9d 81 48 8d 4c 24 20 48 c1 e9 03 48 b8 f1 f1 f1 f1 04 f3 f3 f3 48 89 4c 24 18 4a 89 04 39 <4c> 8d 77 04 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 9f 01 RSP: 0018:ffffc90000007b20 EFLAGS: 00000802 RAX: f3f3f304f1f1f1f1 RBX: ffffffff99ce1278 RCX: 1ffff92000000f68 RDX: 0000000000000000 RSI: ffffffff8be33660 RDI: ffffffff99ce1278 RBP: ffffc90000007bd0 R08: 0000000000000001 R09: 0000000000000000 R10: ffffc90000007ca0 R11: fffff52000000f96 R12: dffffc0000000000 R13: dffffc0000000000 R14: 0000000000000802 R15: dffffc0000000000 FS: 00007ff3767d7880(0000) GS:ffff888125c1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055df1cb1c950 CR3: 000000007da60000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162 debug_object_activate+0xbb/0x420 lib/debugobjects.c:818 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:211 [inline] RIP: 0010:unwind_next_frame+0x1f2/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: c0 49 81 fc ac 72 7d 8b 0f 93 c1 08 c1 0f 85 e8 00 00 00 48 c7 c0 00 00 00 81 4d 89 e7 49 29 c7 49 c1 ef 08 8b 15 1e 2f 4b 0c <8d> 42 ff 44 39 f8 0f 86 65 18 00 00 44 89 f8 4c 8d 2c 85 40 11 e0 RSP: 0018:ffffc90003157118 EFLAGS: 00000206 RAX: ffffffff81000000 RBX: 0000000000000001 RCX: 89542172cfd8f700 RDX: 00000000000a7d74 RSI: ffffffff8be33660 RDI: ffffffff8be33620 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90003157298 R11: fffff5200062ae55 R12: ffffffff81699a23 R13: ffffc90003157298 R14: ffffc90003157248 R15: 000000000000699a __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x18e/0x440 mm/slub.c:4879 tomoyo_check_open_permission+0x2c2/0x3b0 security/tomoyo/file.c:786 security_file_open+0xb1/0x270 security/security.c:3144 do_dentry_open+0x384/0x13f0 fs/open.c:942 vfs_open+0x3b/0x340 fs/open.c:1095 do_open fs/namei.c:3887 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4046 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff376115c3a 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:00007fffd701f9e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055f97de7c930 RCX: 00007ff376115c3a RDX: 0000000000090800 RSI: 000055f97ddf2da0 RDI: 00000000ffffff9c RBP: 000055f97ddf2da0 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000206 R12: 000055f97ddf37b0 R13: 00000000000000ff R14: 000055f975ea1be0 R15: 00007fffd701fc70 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g9753 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=4250 rcu: rcu_preempt kthread starved for 10502 jiffies! g9753 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245