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BUG: KCSAN: data-race in __fsnotify_parent / fsnotify_recalc_mask

write to 0xffff88812fe9ae3c of 4 bytes by task 4118 on cpu 1:
 __fsnotify_recalc_mask fs/notify/mark.c:132 [inline]
 fsnotify_recalc_mask+0x17d/0x1e0 fs/notify/mark.c:147
 fsnotify_add_mark_locked+0x9fa/0xbc0 fs/notify/mark.c:694
 fsnotify_add_inode_mark_locked include/linux/fsnotify_backend.h:548 [inline]
 inotify_new_watch fs/notify/inotify/inotify_user.c:601 [inline]
 inotify_update_watch fs/notify/inotify/inotify_user.c:628 [inline]
 __do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:766 [inline]
 __se_sys_inotify_add_watch+0x53b/0x680 fs/notify/inotify/inotify_user.c:709
 __x64_sys_inotify_add_watch+0x3f/0x50 fs/notify/inotify/inotify_user.c:709
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812fe9ae3c of 4 bytes by task 3908 on cpu 0:
 fsnotify_event_needs_parent fs/notify/fsnotify.c:163 [inline]
 __fsnotify_parent+0x12e/0x440 fs/notify/fsnotify.c:204
 fsnotify_parent include/linux/fsnotify.h:77 [inline]
 fsnotify_file include/linux/fsnotify.h:99 [inline]
 fsnotify_modify include/linux/fsnotify.h:264 [inline]
 do_iter_write+0x4e2/0x5c0 fs/read_write.c:855
 vfs_iter_write+0x4c/0x70 fs/read_write.c:892
 iter_file_splice_write+0x43a/0x790 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1304 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0xb9/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x0000a202

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3908 Comm: syz-executor.5 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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