netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2552 ================================================================== BUG: KCSAN: data-race in data_push_tail / string write to 0xffffffff88e5c190 of 1 bytes by task 6580 on cpu 1: string_nocheck lib/vsprintf.c:657 [inline] string+0x187/0x220 lib/vsprintf.c:735 vsnprintf+0x532/0x890 lib/vsprintf.c:2926 vscnprintf+0x41/0x90 lib/vsprintf.c:2991 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2189 vprintk_store+0x599/0x860 kernel/printk/printk.c:2309 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2448 validate_nla lib/nlattr.c:414 [inline] __nla_validate_parse+0x1227/0x1d00 lib/nlattr.c:635 __nla_parse+0x40/0x60 lib/nlattr.c:732 __nlmsg_parse include/net/netlink.h:789 [inline] nlmsg_parse_deprecated include/net/netlink.h:830 [inline] rtnl_newlink+0xf1/0x12d0 net/core/rtnetlink.c:3970 rtnetlink_rcv_msg+0x5fe/0x6d0 net/core/rtnetlink.c:6951 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2552 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6978 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:742 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2630 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2719 x64_sys_call+0x191e/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff88e5c190 of 8 bytes by task 6579 on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:591 [inline] data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:676 data_alloc+0xfb/0x2e0 kernel/printk/printk_ringbuffer.c:1061 prb_reserve+0x807/0xaf0 kernel/printk/printk_ringbuffer.c:1685 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2448 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline] show_trace_log_lvl+0x4e3/0x560 arch/x86/kernel/dumpstack.c:282 __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0xe8/0x140 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+0x265/0x280 lib/fault-inject.c:174 should_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4923 [inline] slab_alloc_node mm/slub.c:5256 [inline] kmem_cache_alloc_node_noprof+0x57/0x4a0 mm/slub.c:5332 __alloc_skb+0x101/0x320 net/core/skbuff.c:660 alloc_skb include/linux/skbuff.h:1383 [inline] netlink_dump+0x10d/0x8a0 net/netlink/af_netlink.c:2292 __netlink_dump_start+0x43e/0x520 net/netlink/af_netlink.c:2442 netlink_dump_start include/linux/netlink.h:341 [inline] rtnetlink_dump_start net/core/rtnetlink.c:6849 [inline] rtnetlink_rcv_msg+0x552/0x6d0 net/core/rtnetlink.c:6916 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2552 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6978 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:742 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2630 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2719 x64_sys_call+0x191e/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000ffffe3d5 -> 0x61203a2735333131 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 6579 Comm: syz.1.1138 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 ================================================================== rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6978 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:742 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2630 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2719 x64_sys_call+0x191e/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f382ca0efc9 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:00007f382b477038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f382cc65fa0 RCX: 00007f382ca0efc9 RDX: 0000000000040004 RSI: 0000200000000280 RDI: 0000000000000004 RBP: 00007f382b477090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f382cc66038 R14: 00007f382cc65fa0 R15: 00007ffddfbb7cb8