syzbot

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BUG: KCSAN: data-race in __fsnotify_parent / d_shrink_del

read to 0xffff888128c0c0c0 of 4 bytes by task 12796 on cpu 1:
 __fsnotify_parent+0x55/0x230 fs/notify/fsnotify.c:151
 fsnotify_parent include/linux/fsnotify.h:40 [inline]
 fsnotify_path include/linux/fsnotify.h:50 [inline]
 fsnotify_access include/linux/fsnotify.h:240 [inline]
 vfs_read fs/read_write.c:463 [inline]
 vfs_read+0x26c/0x2c0 fs/read_write.c:446
 ksys_read+0xd5/0x1b0 fs/read_write.c:587
 __do_sys_read fs/read_write.c:597 [inline]
 __se_sys_read fs/read_write.c:595 [inline]
 __x64_sys_read+0x4c/0x60 fs/read_write.c:595
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888128c0c0c0 of 4 bytes by task 12800 on cpu 0:
 d_shrink_del+0xd4/0x180 fs/dcache.c:421
 shrink_dentry_list+0x125/0x1c0 fs/dcache.c:1109
 shrink_dcache_sb+0x107/0x1d0 fs/dcache.c:1242
 reconfigure_super+0x31a/0x570 fs/super.c:938
 do_remount fs/namespace.c:2553 [inline]
 do_mount+0x1136/0x14f0 fs/namespace.c:3133
 ksys_mount+0xe8/0x160 fs/namespace.c:3351
 __do_sys_mount fs/namespace.c:3365 [inline]
 __se_sys_mount fs/namespace.c:3362 [inline]
 __x64_sys_mount+0x70/0x90 fs/namespace.c:3362
 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: 12800 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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