KCSAN: data-race in packet_do_bind / packet_getname (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 407ab579 Merge tag 'for-linus' of git://git.kernel.org/pub..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13c15c3a500000
kernel config: https://syzkaller.appspot.com/x/.config?x=671e27f23e60a67b
dashboard link: https://syzkaller.appspot.com/bug?extid=a7e88feac4411e409be4
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [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 maow...@huawei.com net...@vger.kernel.org songliu...@fb.com wil...@google.com xie.h...@gmail.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+a7e88f...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in packet_do_bind / packet_getname

write to 0xffff88810a316cd4 of 4 bytes by task 20174 on cpu 0:
packet_do_bind+0x3d9/0x6f0 net/packet/af_packet.c:3168
packet_bind+0xc3/0xd0 net/packet/af_packet.c:3232
__sys_bind+0x1fd/0x2a0 net/socket.c:1656
__do_sys_bind net/socket.c:1667 [inline]
__se_sys_bind net/socket.c:1665 [inline]
__x64_sys_bind+0x3d/0x50 net/socket.c:1665
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810a316cd4 of 4 bytes by task 20182 on cpu 1:
packet_getname+0x5b/0x1a0 net/packet/af_packet.c:3502
__sys_getsockname+0x10a/0x1b0 net/socket.c:1902
__do_sys_getsockname net/socket.c:1917 [inline]
__se_sys_getsockname net/socket.c:1914 [inline]
__x64_sys_getsockname+0x3e/0x50 net/socket.c:1914
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: 1 PID: 20182 Comm: syz-executor.0 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 20182 Comm: syz-executor.0 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x116/0x15d lib/dump_stack.c:118
panic+0x1e7/0x5fa kernel/panic.c:231
kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
packet_getname+0x5b/0x1a0 net/packet/af_packet.c:3502
__sys_getsockname+0x10a/0x1b0 net/socket.c:1902
__do_sys_getsockname net/socket.c:1917 [inline]
__se_sys_getsockname net/socket.c:1914 [inline]
__x64_sys_getsockname+0x3e/0x50 net/socket.c:1914
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb3e3b5dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000033
RAX: ffffffffffffffda RBX: 0000000000004a00 RCX: 000000000045deb9
RDX: 00000000200002c0 RSI: 0000000020000500 RDI: 0000000000000003
RBP: 000000000118c008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bfd4
R13: 00007ffd1b9adecf R14: 00007fb3e3b5e9c0 R15: 000000000118bfd4
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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.