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BUG: KCSAN: data-race in __mark_inode_dirty / vfs_fsync_range

write to 0xffff888106b11c80 of 8 bytes by task 11406 on cpu 0:
 __mark_inode_dirty+0x1ef/0x6c0 fs/fs-writeback.c:2312
 mark_inode_dirty include/linux/fs.h:2404 [inline]
 generic_write_end+0x157/0x180 fs/buffer.c:2223
 fat_write_end+0x4a/0x160 fs/fat/inode.c:249
 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3671
 __generic_file_write_iter+0x161/0x300 mm/filemap.c:3789
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3821
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 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+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106b11c80 of 8 bytes by task 11416 on cpu 1:
 vfs_fsync_range+0x98/0x120 fs/sync.c:198
 generic_write_sync include/linux/fs.h:2982 [inline]
 generic_file_write_iter+0x103/0x130 mm/filemap.c:3825
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 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+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000804 -> 0x0000000000000007

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11416 Comm: syz-executor.2 Tainted: G        W         5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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