rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10505 jiffies, g=68785, q=932 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10505 (4295005439-4294994934), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10505 jiffies! g68785 f0x2 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:28152 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 4992 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:246 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4855 [inline] RIP: 0010:__lock_acquire+0x3c6/0x2cf0 kernel/locking/lockdep.c:5187 Code: 0e 48 c7 c6 3f 00 0c 8e 67 48 0f b9 3a 90 31 c0 0f b6 98 c4 00 00 00 41 8b 45 20 25 ff 1f 00 00 48 0f a3 05 5c 68 9e 12 73 17 <48> 69 c0 c8 00 00 00 48 8d 88 70 13 e1 93 84 db 75 3f e9 10 02 00 RSP: 0018:ffffc90000a08b80 EFLAGS: 00000047 RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000 RDX: 0000000000080000 RSI: 0000000000004000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffffff84bc873c R09: ffffffff9a737708 R10: dffffc0000000000 R11: ffffed1009ddd663 R12: 0000000000000000 R13: ffff88807d3d68e0 R14: ffff88807d3d5d00 R15: ffff88807d3d6890 FS: 00007f1f7eb44880(0000) GS:ffff88812539c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055557d8d9a38 CR3: 0000000024eec000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166 debug_object_deactivate+0x6c/0x3a0 lib/debugobjects.c:900 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:1898 [inline] __hrtimer_run_queues+0x23a/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:kernel_text_address+0x83/0xe0 kernel/extable.c:116 Code: 5d 83 3d bf 24 a0 0e 01 77 18 48 81 fb 00 10 9b 91 0f 93 c0 48 81 fb 10 12 b3 91 0f 92 c1 84 c8 75 b6 e8 10 10 1b 00 41 89 c6 <84> c0 75 05 e8 14 ac 17 0a 48 89 df e8 9c 95 1f 00 bd 01 00 00 00 RSP: 0018:ffffc900036ff0d8 EFLAGS: 00000212 RAX: 0000000000000001 RBX: 00007f1f7ebd0407 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8c28b740 RDI: ffffffff8c28b700 RBP: 0000000000000001 R08: 0000000000000022 R09: ffffffff8e95cc20 R10: dffffc0000000000 R11: ffffffff81b0e0e0 R12: ffff88807d3d5d00 R13: ffff88807e9e4940 R14: 0000000000000001 R15: 1ffff920006dfe2e __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26 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 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_noprof+0x35c/0x760 mm/slub.c:5308 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2739 do_dentry_open+0x4a8/0x13a0 fs/open.c:924 vfs_open+0x3b/0x340 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x2e08/0x3860 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+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1f7ebd0407 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:00007ffd6a53d050 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f1f7eb44880 RCX: 00007f1f7ebd0407 RDX: 00000000000a0800 RSI: 0000556e9789e2d0 RDI: ffffffffffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000556e83723100 R14: 0000000000000000 R15: 00007ffd6a53d2e0