[ Upstream commitb0522303f6] In exfat_find_last_cluster(), the cluster chain is traversed until the EOF cluster. If the cluster chain includes a loop due to file system corruption, the EOF cluster cannot be traversed, resulting in an infinite loop. If the number of clusters indicated by the file size is inconsistent with the cluster chain length, exfat_find_last_cluster() will return an error, so if this inconsistency is found, the traversal can be aborted without traversing to the EOF cluster. Reported-by: syzbot+f7d147e6db52b1e09dba@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f7d147e6db52b1e09dba Tested-by: syzbot+f7d147e6db52b1e09dba@syzkaller.appspotmail.com Fixes:31023864e6("exfat: add fat entry operations") Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>