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BUG: KCSAN: data-race in d_shrink_del / lookup_fast

write to 0xffff88807864c780 of 4 bytes by task 17091 on cpu 1:
 d_shrink_del+0xcd/0x170 fs/dcache.c:421
 shrink_dentry_list+0xe2/0x1d0 fs/dcache.c:1118
 shrink_dcache_sb+0x106/0x1c0 fs/dcache.c:1242
 reconfigure_super+0x318/0x570 fs/super.c:940
 do_remount fs/namespace.c:2553 [inline]
 do_mount+0x1120/0x1590 fs/namespace.c:3132
 __do_sys_mount fs/namespace.c:3350 [inline]
 __se_sys_mount fs/namespace.c:3327 [inline]
 __x64_sys_mount+0x12b/0x1a0 fs/namespace.c:3327
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88807864c780 of 4 bytes by task 1 on cpu 0:
 d_revalidate fs/namei.c:753 [inline]
 lookup_fast+0x176/0x3a0 fs/namei.c:1479
 open_last_lookups fs/namei.c:3121 [inline]
 path_openat+0x2ba/0x23d0 fs/namei.c:3343
 do_filp_open+0x11e/0x1b0 fs/namei.c:3373
 do_sys_openat2+0x52e/0x680 fs/open.c:1148
 do_sys_open+0xa2/0x110 fs/open.c:1164
 ksys_open include/linux/syscalls.h:1386 [inline]
 __do_sys_open fs/open.c:1170 [inline]
 __se_sys_open fs/open.c:1168 [inline]
 __x64_sys_open+0x50/0x60 fs/open.c:1168
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1 Comm: systemd Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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