syzbot

netlink: 20 bytes leftover after parsing attributes in process `syz-executor.4'.
==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff86e9f26a of 1 bytes by task 13272 on cpu 0:
 string_nocheck lib/vsprintf.c:649 [inline]
 string+0x16c/0x200 lib/vsprintf.c:727
 vsnprintf+0xa09/0xe20 lib/vsprintf.c:2818
 vscnprintf+0x42/0x80 lib/vsprintf.c:2924
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2128
 vprintk_store+0x56f/0x800 kernel/printk/printk.c:2242
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2288
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2322
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2332
 base_sock_release+0x38/0x200 drivers/isdn/mISDN/socket.c:622
 __sock_release net/socket.c:659 [inline]
 sock_close+0x64/0x140 net/socket.c:1402
 __fput+0x2fd/0x5f0 fs/file_table.c:384
 __fput_sync+0x44/0x50 fs/file_table.c:465
 __do_sys_close fs/open.c:1572 [inline]
 __se_sys_close+0xfa/0x1a0 fs/open.c:1557
 __x64_sys_close+0x1f/0x30 fs/open.c:1557
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff86e9f268 of 8 bytes by task 13282 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x893/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2232
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2288
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2322
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2332
 __nla_validate_parse+0x162a/0x1bc0 lib/nlattr.c:621
 __nla_parse+0x40/0x50 lib/nlattr.c:706
 __nlmsg_parse include/net/netlink.h:745 [inline]
 genl_family_rcv_msg_attrs_parse+0x148/0x1a0 net/netlink/genetlink.c:801
 genl_family_rcv_msg_doit net/netlink/genetlink.c:949 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
 genl_rcv_msg+0x470/0x6a0 net/netlink/genetlink.c:1066
 netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1075
 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
 netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368
 netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910
 sock_sendmsg_nosec net/socket.c:730 [inline]
 sock_sendmsg net/socket.c:753 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2541
 ___sys_sendmsg net/socket.c:2595 [inline]
 __sys_sendmsg+0x1e9/0x270 net/socket.c:2624
 __do_sys_sendmsg net/socket.c:2633 [inline]
 __se_sys_sendmsg net/socket.c:2631 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2631
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000100004170 -> 0x0000000100003701

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13282 Comm: syz-executor.4 Not tainted 6.6.0-rc3-syzkaller-00252-ge81a2dabc3f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
==================================================================
syz-executor.4 (13282) used greatest stack depth: 10056 bytes left