netlink: 24 bytes leftover after parsing attributes in process `syz.3.4495'.
==================================================================
BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff86669778 of 8 bytes by task 16671 on cpu 1:
 data_alloc+0x291/0x2c0 kernel/printk/printk_ringbuffer.c:1096
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 dev_vprintk_emit+0x1df/0x210 drivers/base/core.c:4935
 dev_printk_emit+0x82/0xb0 drivers/base/core.c:4946
 __netdev_printk+0x352/0x3e0 net/core/dev.c:11932
 netdev_info+0x99/0xc0 net/core/dev.c:11987
 dev_change_name+0x5a5/0x610 net/core/dev.c:1243
 do_setlink+0x524/0x22c0 net/core/rtnetlink.c:3089
 rtnl_changelink net/core/rtnetlink.c:3723 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3875 [inline]
 rtnl_newlink+0xd9a/0x1200 net/core/rtnetlink.c:4007
 rtnetlink_rcv_msg+0x651/0x710 net/core/rtnetlink.c:6917
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2542
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6944
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x599/0x670 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x5cc/0x6e0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:726
 __sys_sendto+0x1a8/0x230 net/socket.c:2197
 __do_sys_sendto net/socket.c:2204 [inline]
 __se_sys_sendto net/socket.c:2200 [inline]
 __x64_sys_sendto+0x78/0x90 net/socket.c:2200
 x64_sys_call+0x29fa/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86669778 of 8 bytes by task 16802 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:482 [inline]
 desc_push_tail kernel/printk/printk_ringbuffer.c:778 [inline]
 desc_reserve kernel/printk/printk_ringbuffer.c:924 [inline]
 prb_reserve+0x235/0xb60 kernel/printk/printk_ringbuffer.c:1619
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:86
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 __nla_validate_parse+0x1881/0x1e30 lib/nlattr.c:647
 __nla_parse+0x40/0x60 lib/nlattr.c:732
 __nlmsg_parse include/net/netlink.h:764 [inline]
 nlmsg_parse_deprecated include/net/netlink.h:805 [inline]
 rtnl_newlink+0xed/0x1200 net/core/rtnetlink.c:3916
 rtnetlink_rcv_msg+0x651/0x710 net/core/rtnetlink.c:6917
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2542
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6944
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x599/0x670 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x5cc/0x6e0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:726
 ____sys_sendmsg+0x312/0x410 net/socket.c:2583
 ___sys_sendmsg net/socket.c:2637 [inline]
 __sys_sendmsg+0x19d/0x230 net/socket.c:2669
 __do_sys_sendmsg net/socket.c:2674 [inline]
 __se_sys_sendmsg net/socket.c:2672 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2672
 x64_sys_call+0x2734/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xfffffffffffcfd40 -> 0x000000000005aa10

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16802 Comm: syz.3.4495 Not tainted 6.13.0-rc1-syzkaller-00002-gcdd30ebb1b9f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
netlink: 20 bytes leftover after parsing attributes in process `syz.3.4495'.