syzbot

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BUG: KCSAN: data-race in dentry_lru_isolate_shrink / link_path_walk

write to 0xffff88811ec71f00 of 4 bytes by task 10622 on cpu 0:
 d_lru_shrink_move fs/dcache.c:453 [inline]
 dentry_lru_isolate_shrink+0x7b/0x100 fs/dcache.c:1240
 __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:1259
 reconfigure_super+0x267/0x4d0 fs/super.c:940
 do_remount fs/namespace.c:2612 [inline]
 path_mount+0x13c2/0x1c70 fs/namespace.c:3184
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount+0x126/0x180 fs/namespace.c:3390
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3390
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811ec71f00 of 4 bytes by task 10625 on cpu 1:
 __d_entry_type include/linux/dcache.h:391 [inline]
 d_can_lookup include/linux/dcache.h:406 [inline]
 link_path_walk+0x47e/0x730 fs/namei.c:2193
 path_parentat fs/namei.c:2385 [inline]
 filename_parentat+0xf7/0x970 fs/namei.c:2407
 filename_create+0x58/0x3c0 fs/namei.c:3449
 user_path_create fs/namei.c:3524 [inline]
 do_mkdirat+0x5a/0x220 fs/namei.c:3664
 __do_sys_mkdir fs/namei.c:3688 [inline]
 __se_sys_mkdir fs/namei.c:3686 [inline]
 __x64_sys_mkdir+0x32/0x40 fs/namei.c:3686
 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: 10625 Comm: syz-executor.3 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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