KCSAN: data-race in ns_capable / prepare_signal

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 111e91a6 Merge tag 's390-5.10-4' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=114e2516500000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0bbcd06922dbd46
dashboard link: https://syzkaller.appspot.com/bug?extid=05448f228949a437c103
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+05448f...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in ns_capable / prepare_signal

read-write to 0xffff888021027064 of 4 bytes by task 31395 on cpu 0:
ns_capable_common kernel/capability.c:377 [inline]
ns_capable+0x79/0xa0 kernel/capability.c:396
inet_create+0x235/0x640 net/ipv4/af_inet.c:311
__sock_create+0x2cc/0x4f0 net/socket.c:1427
sock_create net/socket.c:1478 [inline]
__sys_socket+0xb0/0x200 net/socket.c:1520
__do_sys_socket net/socket.c:1529 [inline]
__se_sys_socket net/socket.c:1527 [inline]
__x64_sys_socket+0x3b/0x50 net/socket.c:1527
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888021027064 of 4 bytes by task 31394 on cpu 1:
sig_task_ignored kernel/signal.c:94 [inline]
sig_ignored kernel/signal.c:119 [inline]
prepare_signal+0x891/0xda0 kernel/signal.c:962
__send_signal+0x64/0x780 kernel/signal.c:1082
send_signal+0x39f/0x3d0 kernel/signal.c:1242
__group_send_sig_info kernel/signal.c:1281 [inline]
do_notify_parent_cldstop+0x231/0x280 kernel/signal.c:2068
ptrace_stop+0x2aa/0x620 kernel/signal.c:2202
ptrace_signal kernel/signal.c:2491 [inline]
get_signal+0xbed/0x1510 kernel/signal.c:2654
arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
exit_to_user_mode_prepare+0xde/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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31394 Comm: syz-executor.5 Not tainted 5.10.0-rc4-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.