Re: [libvirt] [PATCH] maint: increase stack frame size limit

Eric Blake wrote: > On 05/08/2015 12:23 AM, Roman Bogorodskiy wrote: > > Roman Bogorodskiy wrote: > > > >> Roman Bogorodskiy wrote: > >> > >>> Currently the stack frame size limit is set to 4096 and it started to > >>> cause an error like this: > >>> > >>> virshtest.c:253:1: error: stack frame size of 5512 bytes in function > >>> 'mymain' [-Werror,-Wframe-larger-than=] > >>> mymain(void) > >>> ^ > >>> 1 error generated. > >>> > >>> Increase it to 6144. > >> > >> Worth to mention that it's started to show up after updating to clang > >> 3.6. > > > > Any comments on this? > > Have you reported a possible clang regression bug to the clang folks? > Or is the new clang version the first one to support what was originally > only gcc's -Wframe-larger-than? At any rate, why does clang require a > larger stack than gcc? It sounds like in addition to fixing the > virshtest.c file to quit stack-allocating such a large amount of space, > that you should also be letting the clang compiler folks know about > their weakness. I wasn't absolutely sure that it is a clang problem. However, I did a check now on the same libvirt revision and on the same system with different clang versions and figured out that things work fine with: clang version 3.4.2 (tags/RELEASE_34/dot2-final) but start breaking on: clang version 3.5.2 (tags/RELEASE_352/final) So it indeed makes sense to ask clang developers what's going on; will do that. I'll also try to figure out how to rewrite virshtest.c to quite stack-allocation. Thanks for the feedback!