KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock (4)

[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=10d4e59b500000
kernel config: https://syzkaller.appspot.com/x/.config?x=329e76890d0bf5c3
dashboard link: https://syzkaller.appspot.com/bug?extid=4c2bf55783cf132212f4
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [da...@davemloft.net ktk...@virtuozzo.com ku...@kernel.org linux-...@vger.kernel.org net...@vger.kernel.org pab...@redhat.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+4c2bf5...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock

write to 0xffff88810d8fae30 of 4 bytes by task 20422 on cpu 1:
unix_release_sock+0x2ad/0x650 net/unix/af_unix.c:550
unix_release+0x2f/0x50 net/unix/af_unix.c:859
__sock_release net/socket.c:596 [inline]
sock_close+0x6c/0x150 net/socket.c:1277
__fput+0x243/0x4d0 fs/file_table.c:281
____fput+0x11/0x20 fs/file_table.c:314
task_work_run+0x8e/0x110 kernel/task_work.c:151
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
exit_to_user_mode_prepare+0x13c/0x170 kernel/entry/common.c:191
syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d8fae30 of 4 bytes by task 20425 on cpu 0:
sock_error include/net/sock.h:2217 [inline]
sock_alloc_send_pskb+0xe0/0x470 net/core/sock.c:2309
unix_dgram_sendmsg+0x485/0x15f0 net/unix/af_unix.c:1670
unix_seqpacket_sendmsg+0xc2/0x100 net/unix/af_unix.c:2054
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_sendmmsg+0x335/0x4b0 net/socket.c:2497
__do_sys_sendmmsg net/socket.c:2526 [inline]
__se_sys_sendmmsg net/socket.c:2523 [inline]
__x64_sys_sendmmsg+0x53/0x60 net/socket.c:2523
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: 20425 Comm: syz-executor.3 Not tainted 5.10.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

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