syzbot

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BUG: KCSAN: data-race in dentry_lru_isolate_shrink / link_path_walk

write to 0xffff88810d977180 of 4 bytes by task 13580 on cpu 0:
 d_lru_shrink_move fs/dcache.c:453 [inline]
 dentry_lru_isolate_shrink+0x7b/0x100 fs/dcache.c:1247
 __list_lru_walk_one+0xfb/0x320 mm/list_lru.c:222
 list_lru_walk_one mm/list_lru.c:266 [inline]
 list_lru_walk_node+0x63/0x1a0 mm/list_lru.c:295
 list_lru_walk include/linux/list_lru.h:215 [inline]
 shrink_dcache_sb+0x97/0x1c0 fs/dcache.c:1266
 reconfigure_super+0x267/0x4d0 fs/super.c:887
 do_remount fs/namespace.c:2618 [inline]
 path_mount+0x13e8/0x1ca0 fs/namespace.c:3203
 do_mount fs/namespace.c:3224 [inline]
 __do_sys_mount fs/namespace.c:3432 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3409
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3409
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d977180 of 4 bytes by task 8429 on cpu 1:
 link_path_walk+0x360/0x760 fs/namei.c:2148
 path_lookupat+0x7b/0x560 fs/namei.c:2335
 filename_lookup+0xf2/0x380 fs/namei.c:2369
 user_path_at_empty+0x3b/0x50 fs/namei.c:2649
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:185
 vfs_fstatat fs/stat.c:207 [inline]
 vfs_lstat include/linux/fs.h:3122 [inline]
 __do_sys_newlstat fs/stat.c:362 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:356
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:356
 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: 8429 Comm: syz-executor.2 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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