rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6996/1:b..l (detected by 1, t=10503 jiffies, g=74497, q=114) task:udevd state:R running task stack:23168 pid: 6996 ppid: 3547 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5029 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6375 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6779 irqentry_exit+0x53/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627 Code: 2b 00 74 08 4c 89 f7 e8 0c ac 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc9000352f100 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920006a5e2c RCX: 1ffff920006a5dcc RDX: dffffc0000000000 RSI: ffffffff8aab3d00 RDI: ffffffff8af9fa80 RBP: ffffc9000352f260 R08: dffffc0000000000 R09: fffffbfff2131e19 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920006a5e28 R13: dffffc0000000000 R14: ffffc9000352f160 R15: 0000000000000246 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] is_bpf_text_address+0x1d/0x260 kernel/bpf/core.c:725 kernel_text_address kernel/extable.c:151 [inline] __kernel_text_address+0x94/0x100 kernel/extable.c:105 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323 arch_stack_walk+0xf3/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x53/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3220 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233 kmem_cache_zalloc include/linux/slab.h:711 [inline] lsm_inode_alloc security/security.c:595 [inline] security_inode_alloc+0x24/0x110 security/security.c:1033 inode_init_always+0x939/0xc70 fs/inode.c:232 alloc_inode fs/inode.c:268 [inline] new_inode_pseudo+0x8f/0x210 fs/inode.c:1001 new_inode+0x25/0x1d0 fs/inode.c:1030 shmem_get_inode+0x327/0xad0 mm/shmem.c:2290 shmem_mknod+0x54/0x1b0 mm/shmem.c:2850 lookup_open fs/namei.c:3462 [inline] open_last_lookups fs/namei.c:3532 [inline] path_openat+0x130a/0x2f20 fs/namei.c:3739 do_filp_open+0x21c/0x460 fs/namei.c:3769 do_sys_openat2+0x13b/0x4f0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1280 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fbcc3d789a4 RSP: 002b:00007ffeaba64320 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fbcc3d789a4 RDX: 0000000000080241 RSI: 00007ffeaba64868 RDI: 00000000ffffff9c RBP: 00007ffeaba64868 R08: 0000000000000004 R09: 0000000000000001 R10: 00000000000001b6 R11: 0000000000000246 R12: 0000000000080241 R13: 0000555a9b17a72e R14: 0000000000000001 R15: 0000555a9b195160 rcu: rcu_preempt kthread starved for 10553 jiffies! g74497 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:26168 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5029 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6375 schedule+0x11b/0x1f0 kernel/sched/core.c:6458 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4341 Comm: kworker/u4:10 Not tainted 5.15.179-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker RIP: 0010:validate_chain+0x1f/0x5930 kernel/locking/lockdep.c:3744 Code: 08 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 80 02 00 00 49 89 ce 89 54 24 58 <48> 89 7c 24 70 65 48 8b 04 25 28 00 00 00 48 89 84 24 60 02 00 00 RSP: 0018:ffffc9000328efa0 EFLAGS: 00000086 RAX: 1ffffffff2062ff0 RBX: ffffffff90317f80 RCX: f75173d6b73b5f5f RDX: 0000000000000000 RSI: ffff88802ad18be0 RDI: ffff88802ad18000 RBP: ffffc9000328f250 R08: dffffc0000000000 R09: fffffbfff2131e19 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000006 R13: ffff88802ad18ae8 R14: f75173d6b73b5f5f R15: ffff88802ad18c00 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000235de000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] ipv6_addr_label+0x28/0x1a0 net/ipv6/addrlabel.c:148 ipv6_get_saddr_eval+0x5de/0xea0 net/ipv6/addrconf.c:1623 __ipv6_dev_get_saddr+0x1d3/0x4a0 net/ipv6/addrconf.c:1712 ipv6_dev_get_saddr+0x50e/0xbb0 net/ipv6/addrconf.c:1848 ip6_route_get_saddr include/net/ip6_route.h:145 [inline] ip6_dst_lookup_tail+0xc87/0x11a0 net/ipv6/ip6_output.c:1106 ip6_dst_lookup_flow+0xb5/0x170 net/ipv6/ip6_output.c:1231 send6+0x5b8/0xad0 drivers/net/wireguard/socket.c:139 wg_socket_send_skb_to_peer+0x111/0x1d0 drivers/net/wireguard/socket.c:178 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline] wg_packet_handshake_send_worker+0x1d9/0x310 drivers/net/wireguard/send.c:51 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun hrtimer: interrupt took 1230730833 ns vkms_vblank_simulate: vblank timer overrun