bridge0: received packet on veth1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3957/2:b..l rcu: (detected by 1, t=10502 jiffies, g=381809, q=2328 ncpus=2) task:syz.6.8485 state:R running task stack:24472 pid:3957 tgid:3953 ppid:1943 task_flags:0x2040044c flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7592 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913 Code: ff ff ff e8 20 19 41 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 72 54 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 cf 1c 44 0a cc 48 8d 3d f7 33 da RSP: 0018:ffffc900061ee5c8 EFLAGS: 00000282 RAX: e27a57305d14fa00 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000a93c426b RSI: ffffffff8e6fce08 RDI: ffffffff8c6d9480 RBP: ffff888051403e80 R08: 9600000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8ed5c6e0 R12: ffffffff8ed5c6e0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x514/0x660 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x2b9/0x600 mm/slub.c:5010 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x163/0x610 lib/debugobjects.c:420 debug_objects_fill_pool lib/debugobjects.c:780 [inline] debug_object_activate+0x38d/0x420 lib/debugobjects.c:869 debug_rcu_head_queue kernel/rcu/rcu.h:245 [inline] __call_rcu_common kernel/rcu/tree.c:3166 [inline] call_rcu+0x43/0x8b0 kernel/rcu/tree.c:3301 slab_free_hook mm/slub.c:2712 [inline] slab_free mm/slub.c:6499 [inline] kmem_cache_free+0x471/0x650 mm/slub.c:6626 mempool_free+0xec/0x130 mm/mempool.c:717 bio_endio_bh fs/buffer.c:151 [inline] bh_end_async_write+0x99/0x3b0 fs/buffer.c:401 blk_update_request+0x57b/0xe50 block/blk-mq.c:1016 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1147 nullb_complete_cmd drivers/block/null_blk/main.c:1420 [inline] null_handle_cmd drivers/block/null_blk/main.c:1472 [inline] null_queue_rq+0xc2a/0xe70 drivers/block/null_blk/main.c:1711 null_queue_rqs+0x158/0x260 drivers/block/null_blk/main.c:1725 __blk_mq_flush_list block/blk-mq.c:2827 [inline] blk_mq_dispatch_queue_requests+0x426/0x800 block/blk-mq.c:2872 blk_mq_flush_plug_list+0x428/0x540 block/blk-mq.c:2960 blk_add_rq_to_plug+0x175/0x450 block/blk-mq.c:1386 blk_mq_submit_bio+0x1aaa/0x2a70 block/blk-mq.c:3198 __submit_bio_noacct_mq block/blk-core.c:756 [inline] submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:790 __block_write_full_folio+0x818/0xdd0 fs/buffer.c:1817 blkdev_writepages+0xef/0x1b0 block/fops.c:487 do_writepages+0x338/0x560 mm/page-writeback.c:2560 filemap_writeback mm/filemap.c:387 [inline] filemap_fdatawrite_range mm/filemap.c:412 [inline] filemap_write_and_wait_range+0x335/0x3f0 mm/filemap.c:684 filemap_write_and_wait include/linux/pagemap.h:65 [inline] sync_blockdev block/bdev.c:275 [inline] bdev_release+0x1a0/0x690 block/bdev.c:1171 blkdev_release+0x15/0x20 block/fops.c:682 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:1008 do_group_exit+0x22d/0x2f0 kernel/exit.c:1151 get_signal+0x121b/0x12c0 kernel/signal.c:3039 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff34699ddeb RSP: 002b:00007ff34790df00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffffc RBX: 000000000000000b RCX: 00007ff34699ddeb RDX: 00007ff34790efd0 RSI: 0000000080085502 RDI: 000000000000000b RBP: 00007ff34790efd0 R08: 0000000000000001 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502 R13: 0000000800000000 R14: 0000000000000000 R15: 00007ff346a538f3 rcu: rcu_preempt kthread starved for 251 jiffies! g381809 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 26483 Comm: kworker/1:1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: wg-kex-wg2 wg_packet_handshake_receive_worker RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline] RIP: 0010:lock_acquire+0x7d/0x350 kernel/locking/lockdep.c:5884 Code: e8 a8 34 09 00 84 c0 0f 84 e2 01 00 00 83 3d 89 2d d7 0e 00 0f 84 e9 00 00 00 48 8b b4 24 88 00 00 00 4c 89 e7 e8 13 40 94 00 <83> 3d 6c 2d d7 0e 00 0f 84 e4 00 00 00 65 8b 05 97 9a f1 11 85 c0 RSP: 0018:ffffc90000a17e28 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8000000000000102 RDX: 0000000000000000 RSI: ffffffff8177f24c RDI: 1ffffffff1dab8dc RBP: 1ffff92000142ff4 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90000a17fb8 R11: ffffffff81b27650 R12: ffffffff8ed5c6e0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124dd9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd0c3c01d0 CR3: 000000007cfcc000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x2b9/0x600 mm/slub.c:5010 skb_clone+0x212/0x3a0 net/core/skbuff.c:2119 deliver_clone net/bridge/br_forward.c:125 [inline] maybe_deliver net/bridge/br_forward.c:191 [inline] br_flood+0x3c3/0x8d0 net/bridge/br_forward.c:245 br_handle_frame_finish+0x1119/0x1950 net/bridge/br_input.c:229 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:325 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x989/0x30c0 net/core/dev.c:6151 __netif_receive_skb_one_core net/core/dev.c:6262 [inline] __netif_receive_skb net/core/dev.c:6377 [inline] process_backlog+0x727/0x18b0 net/core/dev.c:6728 __napi_poll+0xaa/0x330 net/core/dev.c:7787 napi_poll net/core/dev.c:7850 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8007 handle_softirqs+0x226/0x860 kernel/softirq.c:645 do_softirq+0x77/0xd0 kernel/softirq.c:546 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 blake2s_compress+0xfa/0x1c00 lib/crypto/x86/blake2s.h:42 blake2s_update+0x140/0x450 lib/crypto/blake2s.c:119 hmac+0x2d1/0x3b0 drivers/net/wireguard/noise.c:332 kdf drivers/net/wireguard/noise.c:360 [inline] mix_dh drivers/net/wireguard/noise.c:413 [inline] wg_noise_handshake_create_response+0x328/0x9f0 drivers/net/wireguard/noise.c:697 wg_packet_send_handshake_response+0x110/0x2d0 drivers/net/wireguard/send.c:94 wg_receive_handshake_packet drivers/net/wireguard/receive.c:154 [inline] wg_packet_handshake_receive_worker+0x6a9/0x10c0 drivers/net/wireguard/receive.c:213 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245