Comment 28 for bug 727064

Actually, why not have both? I think this plan would fit everyone:

1) Apply Linus' patch

Both to 2.13 and 2.14, this would not introduce any issues and would restore back the previous behavior, so applications would still work. As I mentioned before, the disadvantages are minimal.

2) Apply H.J. Lu's patch

This would go to 2.14, but not only to x86 but all architectures, and add an overlap check, and when triggered issue a crash.

This would allow old binaries to keep working on 2.14, but newly compiled ones would crash if they are doing something wrong. This would allow all the users of glibc to fix their code for the impending changes.

3) Remove overlap checks

On 2.15, after a transition period, the overlap checks can be removed, and thus save the few extra cycles.

This has all the advantages of all the proposals, and makes it easy to fix the applications that are using memcpy wrong.