syzbot

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BUG: KCSAN: data-race in list_lru_add / list_lru_count_node

read-write to 0xffff888144375ea8 of 8 bytes by task 4878 on cpu 1:
 list_lru_add+0x26f/0x2a0 mm/list_lru.c:130
 d_lru_add fs/dcache.c:404 [inline]
 retain_dentry+0x20b/0x240 fs/dcache.c:657
 dput+0x10e/0x420 fs/dcache.c:880
 handle_mounts fs/namei.c:1389 [inline]
 step_into+0x43b/0xe80 fs/namei.c:1691
 walk_component+0x190/0x350 fs/namei.c:1867
 link_path_walk+0x471/0x730 fs/namei.c:2182
 path_parentat fs/namei.c:2388 [inline]
 filename_parentat+0xf7/0x970 fs/namei.c:2410
 filename_create+0x58/0x3c0 fs/namei.c:3452
 user_path_create fs/namei.c:3527 [inline]
 do_mkdirat+0x5a/0x220 fs/namei.c:3667
 __do_sys_mkdir fs/namei.c:3691 [inline]
 __se_sys_mkdir fs/namei.c:3689 [inline]
 __x64_sys_mkdir+0x32/0x40 fs/namei.c:3689
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888144375ea8 of 8 bytes by task 17694 on cpu 0:
 list_lru_count_node+0x28/0x30 mm/list_lru.c:195
 list_lru_count include/linux/list_lru.h:132 [inline]
 shrink_dcache_sb+0x14e/0x1c0 fs/dcache.c:1269
 reconfigure_super+0x267/0x4d0 fs/super.c:887
 do_remount fs/namespace.c:2618 [inline]
 path_mount+0x13b1/0x1c10 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17694 Comm: syz-executor.5 Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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