R13: 00007f54f4f96038 R14: 00007f54f4f95fa0 R15: 00007fffe7fab248 ================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff86c6ae48 of 8 bytes by task 16682 on cpu 0: data_alloc+0x308/0x380 kernel/printk/printk_ringbuffer.c:1130 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1727 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 vlan_vid0_add net/8021q/vlan.c:347 [inline] vlan_device_event+0xc29/0xcb0 net/8021q/vlan.c:388 notifier_call_chain kernel/notifier.c:85 [inline] raw_notifier_call_chain+0x72/0x1a0 kernel/notifier.c:453 call_netdevice_notifiers_info net/core/dev.c:2250 [inline] call_netdevice_notifiers_extack net/core/dev.c:2288 [inline] call_netdevice_notifiers net/core/dev.c:2302 [inline] __dev_notify_flags+0x1f0/0x390 net/core/dev.c:-1 netif_change_flags+0xa5/0xc0 net/core/dev.c:9828 do_setlink+0x8fc/0x2860 net/core/rtnetlink.c:3215 rtnl_changelink net/core/rtnetlink.c:3849 [inline] __rtnl_newlink net/core/rtnetlink.c:4022 [inline] rtnl_newlink+0x1086/0x1400 net/core/rtnetlink.c:4159 rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:7076 netlink_rcv_skb+0x11e/0x220 net/netlink/af_netlink.c:2556 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7103 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x5a7/0x680 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x5be/0x6f0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:775 [inline] __sock_sendmsg net/socket.c:790 [inline] __sys_sendto+0x411/0x470 net/socket.c:2252 __do_sys_sendto net/socket.c:2259 [inline] __se_sys_sendto net/socket.c:2255 [inline] __x64_sys_sendto+0x76/0x90 net/socket.c:2255 x64_sys_call+0x2d35/0x3020 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff86c6ae48 of 8 bytes by task 16890 on cpu 1: desc_read kernel/printk/printk_ringbuffer.c:496 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:792 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:938 [inline] prb_reserve+0x21a/0xaf0 kernel/printk/printk_ringbuffer.c:1677 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 __show_trace_log_lvl+0x48b/0x560 arch/x86/kernel/dumpstack.c:302 __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x95/0xd0 lib/dump_stack.c:120 dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x25e/0x270 lib/fault-inject.c:174 should_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4539 [inline] slab_alloc_node mm/slub.c:4897 [inline] kmem_cache_alloc_node_noprof+0x85/0x3d0 mm/slub.c:4989 __alloc_skb+0x2db/0x6f0 net/core/skbuff.c:704 alloc_skb include/linux/skbuff.h:1384 [inline] netlink_alloc_large_skb+0xbf/0xf0 net/netlink/af_netlink.c:1185 netlink_sendmsg+0x40c/0x6f0 net/netlink/af_netlink.c:1875 sock_sendmsg_nosec net/socket.c:775 [inline] __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x532/0x580 net/socket.c:2684 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2738 __sys_sendmmsg+0x185/0x320 net/socket.c:2827 __do_sys_sendmmsg net/socket.c:2854 [inline] __se_sys_sendmmsg net/socket.c:2851 [inline] __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2851 x64_sys_call+0x27aa/0x3020 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xfffffffffffd2e38 -> 0x0000000000072c28 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 16890 Comm: syz.5.2816 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 ==================================================================