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Re: Large-Address awareness on 64 bit systems


On 21/06/2011 4:21 AM, Corinna Vinschen wrote:
Hi Ryan,

On Jun 18 16:32, Ryan Johnson wrote:
- deliberately dlopen-ing two dlls with the same base address and
trying to fork
http://cygwin.com/ml/cygwin-apps/2011-06/msg00047.html

Did you try the ASLR flag for your test DLLs?  Does it help, perhaps?
If the ASLR flag works as I understand it, the DLLs should be moved
into a less dangerous memory area and be then fixed there.
ASLR works pretty well for dlls having static use patterns (including apps which always open the same dlls), from what I can tell. The reason I hadn't done it for that test app is because dlls created and loaded dynamically by apps like gcc bootstrap wouldn't have it set either, and I wanted a consistent way to reproduce the erratic fork problems that they see as a result of the odd base address collision. Similarly, I purposefully avoided rebasing or ASLR-ing my cygwin install while testing the fork patches.

Ryan


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