rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5200/1:b..l rcu: (detected by 1, t=10502 jiffies, g=251249, q=4335 ncpus=2) task:udevd state:R running task stack:23576 pid:5200 tgid:5200 ppid:1 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256 irqentry_exit+0x36/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872 Code: dd 08 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 a2 f9 e9 0e 0f 82 74 02 00 00 8b 35 fa 29 ea 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 b9 dc 08 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc9000381f1e8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e3c45e0 RCX: 00000000e88e9613 RDX: 0000000000000000 RSI: ffffffff8da0398a RDI: ffffffff8bf078c0 RBP: 0000000000000002 R08: 632681dc6f0ac56a R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] is_bpf_text_address+0x36/0x1a0 kernel/bpf/core.c:744 kernel_text_address kernel/extable.c:125 [inline] kernel_text_address+0x8d/0x100 kernel/extable.c:94 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xa6/0x100 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4978 [inline] slab_alloc_node mm/slub.c:5288 [inline] kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5295 kmem_alloc_batch+0x49/0x170 lib/debugobjects.c:371 fill_pool lib/debugobjects.c:403 [inline] debug_objects_fill_pool lib/debugobjects.c:725 [inline] debug_objects_fill_pool+0x23f/0x520 lib/debugobjects.c:697 debug_object_activate+0x10b/0x4c0 lib/debugobjects.c:814 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common.constprop.0+0x35/0xa10 kernel/rcu/tree.c:3108 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:408 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5650 [inline] __kmalloc_noprof+0x32f/0x880 mm/slub.c:5662 kmalloc_noprof include/linux/slab.h:961 [inline] tomoyo_realpath_from_path+0xc2/0x6e0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x274/0x460 security/tomoyo/file.c:822 security_inode_getattr+0x116/0x290 security/security.c:2416 vfs_getattr fs/stat.c:259 [inline] vfs_statx_path fs/stat.c:299 [inline] vfs_statx+0x121/0x3f0 fs/stat.c:356 vfs_fstatat+0x7b/0xf0 fs/stat.c:375 __do_sys_newfstatat+0x97/0x120 fs/stat.c:542 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5d72511b0a RSP: 002b:00007ffe374f5078 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 00005647f59ce410 RCX: 00007f5d72511b0a RDX: 00007ffe374f5080 RSI: 00005647f59bc2a8 RDI: 00000000ffffff9c RBP: 00005647fdf69148 R08: 00063478c1c69200 R09: 00007f5d72c75000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffe374f5080 R14: 0000000000000000 R15: 00063478c1c69200 rcu: rcu_preempt kthread starved for 3172 jiffies! g251249 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:28552 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 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: 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 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 67 6f 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 23 74 2c 00 fb f4 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 0000000000ff36e1 RBX: 0000000000000001 RCX: ffffffff8b5db2a9 RDX: 0000000000000000 RSI: ffffffff8da29329 RDI: ffffffff8bf078c0 RBP: ffffed1003ad0b58 R08: 0000000000000001 R09: ffffed10170a6655 R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001 R13: ffff88801d685ac0 R14: ffffffff90824cd0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124b0d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005647fdf62088 CR3: 0000000059e4a000 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+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x38d/0x500 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148