syzbot

==================================================================
BUG: KCSAN: data-race in link_path_walk / shrink_dentry_list

write to 0xffff888120e850c0 of 4 bytes by task 9497 on cpu 1:
 shrink_dentry_list+0x127/0x540 fs/dcache.c:448
 shrink_dcache_sb+0x188/0x2d0 fs/dcache.c:1321
 reconfigure_super+0x146/0x540 fs/super.c:888
 do_remount fs/namespace.c:2686 [inline]
 path_mount+0x13f9/0x1c40 fs/namespace.c:3346
 do_mount fs/namespace.c:3367 [inline]
 __do_sys_mount fs/namespace.c:3575 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3552
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3552
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888120e850c0 of 4 bytes by task 1825 on cpu 0:
 link_path_walk+0x409/0x990 fs/namei.c:2309
 path_lookupat+0x8b/0x3d0 fs/namei.c:2498
 filename_lookup+0x130/0x310 fs/namei.c:2528
 user_path_at_empty+0x3e/0x110 fs/namei.c:2851
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0xa3/0x3c0 fs/stat.c:221
 vfs_fstatat fs/stat.c:243 [inline]
 vfs_lstat include/linux/fs.h:3287 [inline]
 __do_sys_newlstat fs/stat.c:398 [inline]
 __se_sys_newlstat+0x5d/0x250 fs/stat.c:392
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:392
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00280440 -> 0x00200040

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1825 Comm: syz-executor.1 Not tainted 5.17.0-rc7-syzkaller-00241-gf0e18b03fcaf-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================