syzbot

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BUG: KCSAN: data-race in d_set_mounted / traverse_mounts

write to 0xffff88812b8029c0 of 4 bytes by task 24648 on cpu 0:
 d_set_mounted+0xfc/0x190 fs/dcache.c:1459
 get_mountpoint+0x1be/0x300 fs/namespace.c:740
 lock_mount+0x86/0x1d0 fs/namespace.c:2200
 do_new_mount_fc fs/namespace.c:2817 [inline]
 do_new_mount fs/namespace.c:2876 [inline]
 do_mount+0x1874/0x1bd0 fs/namespace.c:3199
 __do_sys_mount fs/namespace.c:3409 [inline]
 __se_sys_mount+0xd3/0x100 fs/namespace.c:3386
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3386
 do_syscall_64+0x71/0x120 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812b8029c0 of 4 bytes by task 1 on cpu 1:
 __traverse_mounts fs/namei.c:1233 [inline]
 traverse_mounts+0x338/0x410 fs/namei.c:1272
 handle_mounts fs/namei.c:1381 [inline]
 step_into+0x88/0xe70 fs/namei.c:1690
 walk_component+0x190/0x350 fs/namei.c:1866
 link_path_walk+0x462/0x730 fs/namei.c:2179
 path_lookupat+0x7b/0x560 fs/namei.c:2332
 filename_lookup+0x31b/0x380 fs/namei.c:2368
 user_path_at_empty+0x3b/0x50 fs/namei.c:2646
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0xb8/0x2b0 fs/stat.c:202
 vfs_stat include/linux/fs.h:3296 [inline]
 __do_sys_newstat fs/stat.c:361 [inline]
 __se_sys_newstat+0x46/0x250 fs/stat.c:357
 __x64_sys_newstat+0x2d/0x40 fs/stat.c:357
 do_syscall_64+0x71/0x120 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1 Comm: systemd Not tainted 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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