rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7097/1:b..l P10084/1:b..l rcu: (detected by 1, t=10502 jiffies, g=40349, q=176 ncpus=2) task:udevd state:R running task stack:24888 pid:10084 tgid:10084 ppid:5179 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7194 irqentry_exit+0x17b/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:899 [inline] RIP: 0010:class_rcu_destructor include/linux/rcupdate.h:1195 [inline] RIP: 0010:unwind_next_frame+0x3c3/0x1ea0 arch/x86/kernel/unwind_orc.c:495 Code: 41 c7 45 00 00 00 00 00 31 ed e8 38 04 c0 09 85 c0 0f 85 90 03 00 00 48 c7 c7 e0 32 5e 8e 48 8d 35 00 00 00 00 e8 dd 7e 2c 00 d8 f8 35 00 e9 73 fc ff ff 49 81 ff 00 f0 38 92 72 0d 49 81 ff RSP: 0018:ffffc9000417f480 EFLAGS: 00000296 RAX: 0000000000000000 RBX: ffffc9000417f5e0 RCX: ffffc9000417f444 RDX: 0000000000000003 RSI: ffffffff8dc1f48b RDI: ffffffff8bfa35a0 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 000000000000adb1 R12: ffffc9000417f590 R13: ffffc9000417f540 R14: ffffc9000417f5e0 R15: ffffc9000417f574 __unwind_start+0x3d1/0x7f0 arch/x86/kernel/unwind_orc.c:773 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kfree+0x1c7/0x690 mm/slub.c:6882 tomoyo_realpath_from_path+0x19c/0x690 security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path2_perm+0x366/0x700 security/tomoyo/file.c:923 tomoyo_path_rename+0xfc/0x1a0 security/tomoyo/tomoyo.c:300 security_path_rename+0x18e/0x3c0 security/security.c:1518 do_renameat2+0x741/0xa10 fs/namei.c:6051 __do_sys_rename fs/namei.c:6099 [inline] __se_sys_rename fs/namei.c:6097 [inline] __x64_sys_rename+0x17f/0x210 fs/namei.c:6097 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7dc767acc7 RSP: 002b:00007ffecaf3c708 EFLAGS: 00000206 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 000055cc71c4f1e0 RCX: 00007f7dc767acc7 RDX: 000055cc719fd010 RSI: 00007ffecaf3c720 RDI: 00007ffecaf3cb20 RBP: 000055cc71c3f0c0 R08: 00000000000001e0 R09: 0000000000000000 R10: 00000000000001b6 R11: 0000000000000206 R12: 00007ffecaf3c720 R13: 00007ffecaf3cb20 R14: 000055cc4e886100 R15: 000055cc4e886140 task:syz-executor state:R running task stack:23352 pid:7097 tgid:7097 ppid:7092 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7051 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1331 [inline] copy_pmd_range mm/memory.c:1392 [inline] copy_pud_range mm/memory.c:1429 [inline] copy_p4d_range mm/memory.c:1453 [inline] copy_page_range+0x1ddc/0x6ba0 mm/memory.c:1539 dup_mmap+0xbea/0x1e20 mm/mmap.c:1827 dup_mm kernel/fork.c:1529 [inline] copy_mm kernel/fork.c:1581 [inline] copy_process+0x7451/0x7890 kernel/fork.c:2221 kernel_clone+0xfc/0x930 kernel/fork.c:2651 __do_sys_clone+0xd9/0x120 kernel/fork.c:2792 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fce317c3752 RSP: 002b:00007ffedd13aee0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffedd13aee0 RCX: 00007fce317c3752 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffedd13b06c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555754c67d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 000000000006a90e R15: 00007ffedd13b0c0 rcu: rcu_preempt kthread starved for 10558 jiffies! g40349 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:28264 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0xdd/0x390 kernel/sched/core.c:6964 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x21e/0x320 kernel/rcu/tree.c:2285 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 76 78 02 c3 cc cc cc cc 0f 1f 00 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 83 cc 14 00 fb f4 fc 31 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197df0 EFLAGS: 00000242 RAX: 000000000249dd73 RBX: ffff88801e2aa4c0 RCX: ffffffff8b76b4b5 RDX: 0000000000000000 RSI: ffffffff8dc45476 RDI: ffffffff8bfa35a0 RBP: 0000000000000001 R08: 0000000000000001 R09: ffffed10170a673d R10: ffff8880b85339eb R11: 0000000000000000 R12: ffffed1003c55498 R13: 0000000000000001 R14: ffffffff90b736d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881246dc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd97a384380 CR3: 00000000791b0000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x35b/0x4b0 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148