syzbot

==================================================================
BUG: KCSAN: data-race in list_lru_add / list_lru_count_node

write to 0xffff8881264b9128 of 8 bytes by task 18893 on cpu 0:
 list_lru_add+0x245/0x270 mm/list_lru.c:130
 d_lru_add fs/dcache.c:404 [inline]
 retain_dentry+0x223/0x260 fs/dcache.c:657
 dput+0x10e/0x420 fs/dcache.c:873
 path_put+0x1b/0x30 fs/namei.c:496
 free_fs_struct fs/fs_struct.c:91 [inline]
 exit_fs+0xb3/0xe0 fs/fs_struct.c:108
 do_exit+0x44b/0x16e0 kernel/exit.c:801
 do_group_exit+0xcb/0x180 kernel/exit.c:903
 get_signal+0xdee/0x1520 kernel/signal.c:2739
 do_signal+0x25/0x270 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:212 [inline]
 __prepare_exit_to_usermode+0x129/0x230 arch/x86/entry/common.c:246
 __syscall_return_slowpath arch/x86/entry/common.c:329 [inline]
 do_syscall_64+0xb9/0x120 arch/x86/entry/common.c:368
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881264b9128 of 8 bytes by task 18897 on cpu 1:
 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:1262
 reconfigure_super+0x267/0x4d0 fs/super.c:940
 do_remount fs/namespace.c:2611 [inline]
 do_mount+0x1354/0x1bd0 fs/namespace.c:3190
 __do_sys_mount fs/namespace.c:3409 [inline]
 __se_sys_mount+0xd3/0x100 fs/namespace.c:3386
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3386
 do_syscall_64+0x71/0x120 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18897 Comm: syz-executor.0 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================