syzbot

==================================================================
BUG: KCSAN: data-race in d_set_mounted / link_path_walk.part.0

write to 0xffff8881298d6d80 of 4 bytes by task 23000 on cpu 1:
 d_set_mounted+0x193/0x1c0 fs/dcache.c:1440
 get_mountpoint+0x13d/0x300 fs/namespace.c:724
 lock_mount+0xa0/0x1a0 fs/namespace.c:2142
 do_add_mount+0x30/0x1e0 fs/namespace.c:2708
 do_new_mount_fc fs/namespace.c:2771 [inline]
 do_new_mount fs/namespace.c:2824 [inline]
 do_mount+0x12a1/0x14f0 fs/namespace.c:3107
 __do_sys_mount fs/namespace.c:3316 [inline]
 __se_sys_mount fs/namespace.c:3293 [inline]
 __x64_sys_mount+0x12d/0x1a0 fs/namespace.c:3293
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881298d6d80 of 4 bytes by task 23002 on cpu 0:
 link_path_walk.part.0+0x27b/0xab0 fs/namei.c:2204
 link_path_walk fs/namei.c:2172 [inline]
 path_openat+0x150/0x3150 fs/namei.c:3606
 do_filp_open+0x11e/0x1b0 fs/namei.c:3637
 do_sys_openat2+0x4f5/0x620 fs/open.c:1149
 do_sys_open+0xa3/0x110 fs/open.c:1165
 ksys_open include/linux/syscalls.h:1386 [inline]
 __do_sys_creat fs/open.c:1233 [inline]
 __se_sys_creat fs/open.c:1231 [inline]
 __x64_sys_creat+0x45/0x60 fs/open.c:1231
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23002 Comm: syz-executor.0 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================