bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) net_ratelimit: 61131 callbacks suppressed ================================================================== BUG: KCSAN: data-race in data_push_tail / vsnprintf write to 0xffffffff8910a020 of 2 bytes by interrupt on cpu 1: vsnprintf+0x2ce/0x860 lib/vsprintf.c:2898 vscnprintf+0x41/0x90 lib/vsprintf.c:3012 printk_sprint+0x30/0x2c0 kernel/printk/printk.c:2192 vprintk_store+0x57b/0x910 kernel/printk/printk.c:2312 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2402 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2451 br_fdb_update+0x431/0x460 net/bridge/br_fdb.c:1003 br_handle_frame_finish+0x340/0xfc0 net/bridge/br_input.c:144 br_nf_hook_thresh+0x233/0x270 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x550/0x580 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x1fa/0x2e0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x52b/0xbd0 net/bridge/br_netfilter_hooks.c:508 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x85f/0xa60 net/bridge/br_input.c:442 __netif_receive_skb_core+0x5b1/0x1950 net/core/dev.c:6039 __netif_receive_skb_one_core net/core/dev.c:6150 [inline] __netif_receive_skb net/core/dev.c:6265 [inline] process_backlog+0x25b/0x670 net/core/dev.c:6617 __napi_poll+0x5f/0x310 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7896 handle_softirqs+0xb9/0x280 kernel/softirq.c:622 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:1063 smpboot_thread_fn+0x32a/0x510 kernel/smpboot.c:160 kthread+0x488/0x510 kernel/kthread.c:463 ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 read to 0xffffffff8910a020 of 8 bytes by interrupt on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:608 [inline] data_push_tail+0x100/0x470 kernel/printk/printk_ringbuffer.c:693 data_alloc+0x11b/0x390 kernel/printk/printk_ringbuffer.c:1089 prb_reserve+0x8d7/0xae0 kernel/printk/printk_ringbuffer.c:1724 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2302 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2402 vprintk_deferred kernel/printk/printk.c:4676 [inline] _printk_deferred+0x82/0xb0 kernel/printk/printk.c:4685 ___ratelimit+0x43a/0x460 lib/ratelimit.c:86 net_ratelimit+0x1c/0x30 net/core/utils.c:40 br_fdb_update+0x2a6/0x460 net/bridge/br_fdb.c:1002 br_handle_frame_finish+0x340/0xfc0 net/bridge/br_input.c:144 br_nf_hook_thresh+0x233/0x270 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x550/0x580 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x1fa/0x2e0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x52b/0xbd0 net/bridge/br_netfilter_hooks.c:508 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x85f/0xa60 net/bridge/br_input.c:442 __netif_receive_skb_core+0x5b1/0x1950 net/core/dev.c:6039 __netif_receive_skb_one_core net/core/dev.c:6150 [inline] __netif_receive_skb net/core/dev.c:6265 [inline] process_backlog+0x25b/0x670 net/core/dev.c:6617 __napi_poll+0x5f/0x310 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7896 handle_softirqs+0xb9/0x280 kernel/softirq.c:622 do_softirq+0x45/0x60 kernel/softirq.c:523 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock_bh+0x18/0x20 kernel/locking/spinlock.c:210 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:890 [inline] nsim_dev_trap_report_work+0x52b/0x630 drivers/net/netdevsim/dev.c:921 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3340 worker_thread+0x6bc/0x8b0 kernel/workqueue.c:3421 kthread+0x488/0x510 kernel/kthread.c:463 ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 value changed: 0x00000000ffffedf2 -> 0x6567646972623401 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 10166 Comm: kworker/u8:18 Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: events_unbound nsim_dev_trap_report_work ================================================================== net_ratelimit: 56775 callbacks suppressed bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)