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http://rockliao.blogbus.com/logs/10691620.html

When I was a fresh engineer, what's the most complex problems?Maybe that's the system crash. I have just met a system crash issue today but in nowadays, things goes different.I have worked on our current system platform for nearly 2 years so many things become easy, it seems that experience is so important.

Issue description:

When a huge DHCP packet is sent from the terminal device and our DHCP snoop function is on, the system will crash immdiately. Level 2 bug, high security level with a fool mistake.

That is because when a big packet which is out of our allocated memory comes, we just copy it to the memory by the packet length, that's very dangerous. This is officially called "memory overflow", which is deadly to the embeded system.Actually, this fool mistake should be not brougth in by a experienced engineer, how it happenned? God knows...hope not to see such problems again.

Anyway, there is something gratified too.Now we can  found out the root cause of system crash issue very rapidly, for example this problem just took me half an hour to fix it. We have many method to orient this type of problems.

明天请同事吃饭唱歌，好久没唱歌了。最近听歌不多，周杰伦的《蒲公英的约定》怎么听都觉得歌词太幼稚了一点，王力宏的声音很磁性，林俊杰的永远都很梦幻，新人张杰的好几首歌还是蛮好听的。