syzbot

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BUG: KCSAN: data-race in d_lru_shrink_move / lookup_fast

write to 0xffff88812558b480 of 4 bytes by task 28849 on cpu 1:
 d_lru_shrink_move+0x5c/0xc0 fs/dcache.c:453
 dentry_lru_isolate_shrink+0x5e/0x90 fs/dcache.c:1221
 __list_lru_walk_one+0x110/0x390 mm/list_lru.c:232
 list_lru_walk_one+0x84/0xb0 mm/list_lru.c:276
 list_lru_walk_node+0x4c/0x190 mm/list_lru.c:305
 list_lru_walk include/linux/list_lru.h:215 [inline]
 shrink_dcache_sb+0xa1/0x1d0 fs/dcache.c:1240
 reconfigure_super+0x31a/0x570 fs/super.c:940
 do_remount fs/namespace.c:2553 [inline]
 do_mount+0x1136/0x14f0 fs/namespace.c:3098
 __do_sys_mount fs/namespace.c:3316 [inline]
 __se_sys_mount fs/namespace.c:3293 [inline]
 __x64_sys_mount+0x12d/0x1a0 fs/namespace.c:3293
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812558b480 of 4 bytes by task 28850 on cpu 0:
 d_revalidate fs/namei.c:765 [inline]
 lookup_fast+0x1ba/0x6c0 fs/namei.c:1690
 walk_component+0x6f/0x9c0 fs/namei.c:1911
 lookup_last fs/namei.c:2391 [inline]
 path_lookupat.isra.0+0x129/0x2e0 fs/namei.c:2436
 filename_lookup+0x145/0x2b0 fs/namei.c:2466
 user_path_at_empty+0x4c/0x70 fs/namei.c:2746
 user_path_at include/linux/namei.h:58 [inline]
 do_faccessat+0x137/0x470 fs/open.c:398
 __do_sys_access fs/open.c:450 [inline]
 __se_sys_access fs/open.c:448 [inline]
 __x64_sys_access+0x3f/0x50 fs/open.c:448
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28850 Comm: blkid Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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