syzbot

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BUG: KCSAN: data-race in ns_capable / proc_cgroup_show

write to 0xffff8880a690d0a4 of 4 bytes by task 15912 on cpu 0:
 ns_capable_common kernel/capability.c:377 [inline]
 ns_capable+0x86/0xb0 kernel/capability.c:396
 netlink_allowed net/netlink/af_netlink.c:913 [inline]
 netlink_sendmsg+0x3b3/0x7a0 net/netlink/af_netlink.c:1873
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2359
 ___sys_sendmsg net/socket.c:2413 [inline]
 __sys_sendmsg+0x1df/0x260 net/socket.c:2446
 __do_sys_sendmsg net/socket.c:2455 [inline]
 __se_sys_sendmsg net/socket.c:2453 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2453
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a690d0a4 of 4 bytes by task 5064 on cpu 1:
 proc_cgroup_show+0x3b3/0x6a0 kernel/cgroup/cgroup.c:5856
 proc_single_show+0x84/0x100 fs/proc/base.c:766
 seq_read+0x2ee/0x900 fs/seq_file.c:208
 vfs_read+0x16d/0x5e0 fs/read_write.c:479
 ksys_read+0xce/0x180 fs/read_write.c:607
 __do_sys_read fs/read_write.c:617 [inline]
 __se_sys_read fs/read_write.c:615 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:615
 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: 5064 Comm: systemd-journal Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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