KCSAN: data-race in netlink_insert / netlink_sendmsg (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cd796ed3 Merge tag 'trace-v5.10-rc7' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12ba0f9b500000
kernel config: https://syzkaller.appspot.com/x/.config?x=329e76890d0bf5c3
dashboard link: https://syzkaller.appspot.com/bug?extid=a06e7056c0085906c3ff
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [0x7f4...@gmail.com and...@kernel.org a...@kernel.org b...@vger.kernel.org dan...@iogearbox.net da...@davemloft.net john.fa...@gmail.com ka...@fb.com kps...@chromium.org ku...@kernel.org linux-...@vger.kernel.org mkub...@suse.cz net...@vger.kernel.org songliu...@fb.com y...@fb.com]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a06e70...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in netlink_insert / netlink_sendmsg

write to 0xffff888015277340 of 1 bytes by task 26436 on cpu 1:
netlink_insert+0x636/0x8e0 net/netlink/af_netlink.c:587
netlink_autobind+0xa9/0x150 net/netlink/af_netlink.c:832
netlink_sendmsg+0x47c/0x7c0 net/netlink/af_netlink.c:1882
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg net/socket.c:671 [inline]
____sys_sendmsg+0x352/0x4c0 net/socket.c:2353
___sys_sendmsg net/socket.c:2407 [inline]
__sys_sendmsg+0x1e2/0x260 net/socket.c:2440
__do_sys_sendmsg net/socket.c:2449 [inline]
__se_sys_sendmsg net/socket.c:2447 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2447
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888015277340 of 1 bytes by task 26399 on cpu 0:
netlink_sendmsg+0x26c/0x7c0 net/netlink/af_netlink.c:1881
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg net/socket.c:671 [inline]
____sys_sendmsg+0x352/0x4c0 net/socket.c:2353
___sys_sendmsg net/socket.c:2407 [inline]
__sys_sendmsg+0x1e2/0x260 net/socket.c:2440
__do_sys_sendmsg net/socket.c:2449 [inline]
__se_sys_sendmsg net/socket.c:2447 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2447
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26399 Comm: syz-executor.0 Not tainted 5.10.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.