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BUG: KCSAN: data-race in fsnotify_conn_mask / fsnotify_recalc_mask

write to 0xffff8880bb794524 of 4 bytes by task 24576 on cpu 1:
 __fsnotify_recalc_mask fs/notify/mark.c:132 [inline]
 fsnotify_recalc_mask+0x154/0x1b0 fs/notify/mark.c:147
 fanotify_add_mark+0x209/0x280 fs/notify/fanotify/fanotify_user.c:791
 do_fanotify_mark+0x92f/0x990 fs/notify/fanotify/fanotify_user.c:830
 __do_sys_fanotify_mark fs/notify/fanotify/fanotify_user.c:1180 [inline]
 __se_sys_fanotify_mark fs/notify/fanotify/fanotify_user.c:1176 [inline]
 __x64_sys_fanotify_mark+0x60/0x70 fs/notify/fanotify/fanotify_user.c:1176
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880bb794524 of 4 bytes by task 24580 on cpu 0:
 fsnotify_conn_mask+0x53/0x70 fs/notify/mark.c:116
 fanotify_add_mark+0x1e1/0x280 fs/notify/fanotify/fanotify_user.c:790
 do_fanotify_mark+0x92f/0x990 fs/notify/fanotify/fanotify_user.c:830
 __do_sys_fanotify_mark fs/notify/fanotify/fanotify_user.c:1180 [inline]
 __se_sys_fanotify_mark fs/notify/fanotify/fanotify_user.c:1176 [inline]
 __x64_sys_fanotify_mark+0x60/0x70 fs/notify/fanotify/fanotify_user.c:1176
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24580 Comm: syz-executor.3 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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