[moderation] [net?] [nfc?] KCSAN: data-race in llcp_raw_sock_bind / llcp_sock_getname

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1c892cdd8fe0 Merge tag 'vfs-6.8-rc6.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1009cf94180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7507056e4ee79a
dashboard link: https://syzkaller.appspot.com/bug?extid=7eae05af95180a023d2b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [da...@davemloft.net edum...@google.com krzysztof...@linaro.org 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.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/139c3c1075e8/disk-1c892cdd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/84baf552e6fb/vmlinux-1c892cdd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bec5bd9af52d/bzImage-1c892cdd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7eae05...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in llcp_raw_sock_bind / llcp_sock_getname

write to 0xffff888167154700 of 8 bytes by task 10196 on cpu 1:
llcp_raw_sock_bind+0x131/0x200 net/nfc/llcp_sock.c:188
__sys_bind+0x157/0x1c0 net/socket.c:1847
__do_sys_bind net/socket.c:1858 [inline]
__se_sys_bind net/socket.c:1856 [inline]
__x64_sys_bind+0x41/0x50 net/socket.c:1856
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888167154700 of 8 bytes by task 10197 on cpu 0:
llcp_sock_getname+0x3a/0x1b0 net/nfc/llcp_sock.c:510
sk_getsockopt+0xc78/0x1680 net/core/sock.c:1826
do_sock_getsockopt+0x9e/0x190 net/socket.c:2365
__sys_getsockopt+0x199/0x200 net/socket.c:2402
__do_sys_getsockopt net/socket.c:2412 [inline]
__se_sys_getsockopt net/socket.c:2409 [inline]
__x64_sys_getsockopt+0x66/0x80 net/socket.c:2409
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000000 -> 0xffff888101f4d800

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10197 Comm: syz-executor.2 Not tainted 6.8.0-rc5-syzkaller-00121-g1c892cdd8fe0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================


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[syzbot]

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