KCSAN: data-race in capable / do_task_stat

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 509a1542 Merge tag '5.10-rc6-smb3-fixes' of git://git.samb..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16d8b0e5500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=c7caaae3ba272f7ef6fc
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-secu...@vger.kernel.org se...@hallyn.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+c7caaa...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in capable / do_task_stat

read-write to 0xffff888018c5c064 of 4 bytes by task 16523 on cpu 1:
ns_capable_common kernel/capability.c:377 [inline]
ns_capable kernel/capability.c:396 [inline]
capable+0x78/0xa0 kernel/capability.c:449
sock_setsockopt+0x6c5/0x1ef0 net/core/sock.c:896
__sys_setsockopt+0x326/0x450 net/socket.c:2128
__do_sys_setsockopt net/socket.c:2143 [inline]
__se_sys_setsockopt net/socket.c:2140 [inline]
__x64_sys_setsockopt+0x62/0x70 net/socket.c:2140
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888018c5c064 of 4 bytes by task 1 on cpu 0:
do_task_stat+0x956/0x1070 fs/proc/array.c:549
proc_tgid_stat+0x2f/0x40 fs/proc/array.c:633
proc_single_show+0x84/0x100 fs/proc/base.c:775
seq_read_iter+0x2ef/0x8e0 fs/seq_file.c:228
seq_read+0x221/0x260 fs/seq_file.c:159
vfs_read+0x154/0x5c0 fs/read_write.c:494
ksys_read+0xce/0x180 fs/read_write.c:634
__do_sys_read fs/read_write.c:644 [inline]
__se_sys_read fs/read_write.c:642 [inline]
__x64_sys_read+0x3e/0x50 fs/read_write.c:642
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: 1 Comm: systemd Not tainted 5.10.0-rc6-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.