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Re: [Xen-devel] [Fwd: stack overflow "cause" found]

On 26 Jul 2006, at 22:49, Rik van Riel wrote:

Xen really should not be doing this. We could either uninline some of
these functions, or try gcc -O2 or gcc -Os.
OK, with -Os it doesn't quite build due to the built-ins not being
inlined.  With -O2 the stack usage changes dramatically...
It would be nice if -O2 worked. Quite a scary change give the amount of inline asm though...

Not only does -O2 seem to work, but without it we get stack
overflows and things suddenly stop working.

I've been beating up my x86-64 system with a few VT and paravirt
guests for over an hour now, and it no longer crashes.  Without
-O2, I can make it crash within minutes...

We only avoided -O2 on debug builds. It's trivial to add it back in. Seems gcc is just really dumb with anything less. I'll add it back in for debug builds. I also made the stack space larger, so we'll be double-protected from overflows in future. :-)

 -- Keir

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