rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5922/1:b..l rcu: (detected by 0, t=10502 jiffies, g=23925, q=618 ncpus=2) task:udevd state:R running task stack:23128 pid:5922 tgid:5922 ppid:5231 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0x501/0x2390 arch/x86/kernel/unwind_orc.c:512 Code: 84 c0 48 89 54 24 08 48 89 34 24 0f 85 4d 18 00 00 4c 89 e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 63 18 00 00 0f b7 1e c1 eb 0b <80> e3 01 48 8b 44 24 28 0f b6 04 28 84 c0 4c 8b 7c 24 70 0f 85 6d RSP: 0018:ffffc900042af098 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8ff9a2e8 RDX: ffffffff9086bde0 RSI: ffffffff9086bde4 RDI: ffffffff8c0361a0 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8173bd35 R10: ffffc900042af1b8 R11: ffffffff81ac3430 R12: ffffffff9086bde5 R13: ffffc900042af1b8 R14: ffffc900042af168 R15: ffffffff8173bd35 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:5366 [inline] __kmalloc_noprof+0x411/0x7f0 mm/slub.c:5378 kmalloc_noprof include/linux/slab.h:960 [inline] tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x1c1/0x3b0 security/tomoyo/file.c:771 security_file_open+0xb1/0x270 security/security.c:3183 do_dentry_open+0x384/0x13f0 fs/open.c:942 vfs_open+0x3b/0x340 fs/open.c:1095 do_open fs/namei.c:3895 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4054 do_filp_open+0x1fa/0x410 fs/namei.c:4081 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/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9575915c3a RSP: 002b:00007ffdb7d36d48 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffdb7d36d80 RCX: 00007f9575915c3a RDX: 0000000000090800 RSI: 00007ffdb7d37180 RDI: 00000000ffffff9c RBP: 0000000000000007 R08: 0000564377f17640 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000564377f20f10 R13: 00007ffdb7d37980 R14: 00007ffdb7d37580 R15: 00007ffdb7d37180 rcu: rcu_preempt kthread starved for 10326 jiffies! g23925 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:27000 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 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+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x47c/0x820 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 93 d8 25 00 f3 0f 1e fa fb f4 48 e7 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8e007d80 EFLAGS: 000002c6 RAX: ae0982c018716900 RBX: ffffffff81968448 RCX: ae0982c018716900 RDX: 0000000000000001 RSI: ffffffff8dbbb53e RDI: ffffffff8c036200 RBP: ffffffff8e007ea8 R08: ffff8880b8632f9b R09: 1ffff110170c65f3 R10: dffffc0000000000 R11: ffffed10170c65f4 R12: ffffffff8fc3ce30 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1c12a38 FS: 0000000000000000(0000) GS:ffff8881259f0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556e96a5c8 CR3: 000000005e31a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:756 start_kernel+0x3a9/0x410 init/main.c:1109 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147