syzbot

==================================================================
BUG: KCSAN: data-race in __d_lookup_done / __dentry_kill

write to 0xffff8881316c8cc0 of 4 bytes by task 1046 on cpu 0:
 __d_lookup_done+0x82/0x1d0 fs/dcache.c:2683
 d_lookup_done include/linux/dcache.h:373 [inline]
 __lookup_slow+0x204/0x280 fs/namei.c:1630
 lookup_slow fs/namei.c:1646 [inline]
 walk_component+0x2a5/0x350 fs/namei.c:1942
 link_path_walk+0x4ba/0x780 fs/namei.c:2265
 path_lookupat+0x7b/0x570 fs/namei.c:2420
 filename_lookup+0xff/0x390 fs/namei.c:2454
 user_path_at_empty+0x3b/0x50 fs/namei.c:2734
 user_path_at include/linux/namei.h:60 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:203
 vfs_fstatat fs/stat.c:225 [inline]
 vfs_lstat include/linux/fs.h:3384 [inline]
 __do_sys_newlstat fs/stat.c:380 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:374
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:374
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881316c8cc0 of 4 bytes by task 994 on cpu 1:
 dentry_unlist fs/dcache.c:547 [inline]
 __dentry_kill+0x1ef/0x4e0 fs/dcache.c:578
 dentry_kill fs/dcache.c:695 [inline]
 dput+0xc6/0x360 fs/dcache.c:888
 handle_mounts fs/namei.c:1474 [inline]
 step_into+0x442/0xec0 fs/namei.c:1772
 walk_component+0x190/0x350 fs/namei.c:1948
 link_path_walk+0x4ba/0x780 fs/namei.c:2265
 path_openat+0x1a0/0x20b0 fs/namei.c:3490
 do_filp_open+0xd9/0x1f0 fs/namei.c:3521
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_open fs/open.c:1211 [inline]
 __se_sys_open fs/open.c:1207 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1207
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x10000004 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 994 Comm: systemd-udevd Not tainted 5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================