rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5200/1:b..l P6190/2:b..l P6147/1:b..l rcu: (detected by 0, t=10502 jiffies, g=13809, q=1162 ncpus=2) task:udevd state:R running task stack:26808 pid:6147 tgid:6147 ppid:5200 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000213f070 EFLAGS: 00000206 RAX: 22297f3488a63400 RBX: 0000000000000000 RCX: 22297f3488a63400 RDX: 00000000f9bfe4d4 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: ffffffff81d0f976 R08: ffffffff81d0f976 R09: ffffffff8e13f2e0 R10: ffffc9000213f1f8 R11: ffffffff81ad9d50 R12: 0000000000000002 R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] is_bpf_text_address+0x47/0x2b0 kernel/bpf/core.c:747 kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/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+0x1c0/0x660 mm/slub.c:6882 tomoyo_realpath_from_path+0x598/0x5d0 security/tomoyo/realpath.c:286 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:2636 do_dentry_open+0x384/0x14e0 fs/open.c:939 vfs_open+0x3b/0x340 fs/open.c:1094 do_open fs/namei.c:4627 [inline] path_openat+0x2de0/0x3840 fs/namei.c:4786 do_filp_open+0x1fa/0x410 fs/namei.c:4813 do_sys_openat2+0x121/0x200 fs/open.c:1391 do_sys_open fs/open.c:1397 [inline] __do_sys_openat fs/open.c:1413 [inline] __se_sys_openat fs/open.c:1408 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1408 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f07660a7407 RSP: 002b:00007ffeb9d2db10 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f0766770880 RCX: 00007f07660a7407 RDX: 0000000000080000 RSI: 00007ffeb9d2dc90 RDI: ffffffffffffff9c RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055f2a98c27f5 R13: 000055f2a98c27f5 R14: 0000000000000001 R15: 000055f2a98dd140 task:syz-executor state:R running task stack:27592 pid:6190 tgid:6190 ppid:5955 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000409f9e0 EFLAGS: 00000206 RAX: 829778594b936200 RBX: 0000000000000000 RCX: 829778594b936200 RDX: 000000001f1241d9 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: ffffffff82318a05 R08: ffffffff82318a05 R09: ffffffff8e13f2e0 R10: ffff888057580a48 R11: ffffffff81ad9d50 R12: 0000000000000002 R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline] percpu_ref_tryget+0x31/0x180 include/linux/percpu-refcount.h:266 css_tryget include/linux/cgroup_refcnt.h:45 [inline] get_mem_cgroup_from_objcg+0x108/0x1d0 include/linux/memcontrol.h:520 __memcg_slab_post_alloc_hook+0x124/0x730 mm/memcontrol.c:3185 memcg_slab_post_alloc_hook mm/slub.c:2338 [inline] slab_post_alloc_hook mm/slub.c:4964 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_lru_noprof+0x41f/0x6e0 mm/slub.c:5286 __d_alloc+0x37/0x6f0 fs/dcache.c:1730 d_alloc+0x4b/0x190 fs/dcache.c:1809 lookup_one_qstr_excl+0xdc/0x360 fs/namei.c:1743 __start_dirop fs/namei.c:2866 [inline] start_dirop fs/namei.c:2875 [inline] filename_create+0x209/0x360 fs/namei.c:4878 do_symlinkat+0xef/0x420 fs/namei.c:5600 __do_sys_symlinkat fs/namei.c:5628 [inline] __se_sys_symlinkat fs/namei.c:5625 [inline] __x64_sys_symlinkat+0x95/0xb0 fs/namei.c:5625 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd0baf8ecc7 RSP: 002b:00007ffd809cf718 EFLAGS: 00000206 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd0baf8ecc7 RDX: 00007fd0bb0158e4 RSI: 00000000ffffff9c RDI: 00007ffd809cf7b0 RBP: 00007ffd809cf75c R08: 0000000000000013 R09: 00007ffd809cf467 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000004 R13: 00000000000927c0 R14: 0000000000020e33 R15: 00007ffd809cf7b0 task:udevd state:R running task stack:25360 pid:5200 tgid:5200 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7050 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7074 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xfd/0x110 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock+0x190/0x1f0 kernel/sched/wait.c:127 sock_def_readable+0x1eb/0x530 net/core/sock.c:3611 __netlink_sendskb net/netlink/af_netlink.c:1263 [inline] netlink_sendskb+0xa1/0x140 net/netlink/af_netlink.c:1269 netlink_unicast+0x397/0x9e0 net/netlink/af_netlink.c:1359 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737 __sock_sendmsg net/socket.c:752 [inline] ____sys_sendmsg+0x577/0x880 net/socket.c:2610 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664 __sys_sendmsg net/socket.c:2696 [inline] __do_sys_sendmsg net/socket.c:2701 [inline] __se_sys_sendmsg net/socket.c:2699 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2699 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f07660a7407 RSP: 002b:00007ffeb9d366c0 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f0766770880 RCX: 00007f07660a7407 RDX: 0000000000000000 RSI: 00007ffeb9d36720 RDI: 0000000000000004 RBP: 000055f2ba84f830 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000cc R13: 000055f2ba8199e0 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10618 jiffies! g13809 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:27728 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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+0x599/0xb30 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6184 Comm: syz.0.48 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:kvm_apic_sw_enabled arch/x86/kvm/lapic.h:192 [inline] RIP: 0010:kvm_lapic_enabled arch/x86/kvm/lapic.h:203 [inline] RIP: 0010:vcpu_enter_guest arch/x86/kvm/x86.c:11284 [inline] RIP: 0010:vcpu_run+0x6684/0x76b0 arch/x86/kvm/x86.c:11639 Code: 00 08 00 00 48 21 c3 75 7e e8 b8 b7 7a 00 e9 71 03 00 00 f3 0f 1e fa 48 81 c3 99 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 7d 09 00 00 0f b6 1b 31 ff 89 de e8 88 ba 7a 00 85 db RSP: 0018:ffffc9000401f560 EFLAGS: 00000802 RAX: 0000000000000000 RBX: ffff888077834e99 RCX: ffff88801d3a9e80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000401f990 R08: ffffffff8fa22f77 R09: 1ffffffff1f445ee R10: dffffc0000000000 R11: fffffbfff1f445ef R12: ffff88807b082c38 R13: 1ffff1100f61052e R14: ffff88807b082978 R15: dffffc0000000000 FS: 00007ffab4fc26c0(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000003235e000 CR4: 00000000003526f0 Call Trace: kvm_arch_vcpu_ioctl_run+0x1148/0x1c90 arch/x86/kvm/x86.c:11984 kvm_vcpu_ioctl+0x99a/0xed0 virt/kvm/kvm_main.c:4492 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ffab418f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffab4fc2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffab43e5fa0 RCX: 00007ffab418f749 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 00007ffab4213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffab43e6038 R14: 00007ffab43e5fa0 R15: 00007ffda04632f8