On Wed, Oct 21, 2009 at 07:28:54PM +0200, Paolo Bonzini wrote: >> I've uploaded them here: >> http://www.kernel.org/pub/linux/kernel/people/mst/ >> you can't see them in mirrors yet but will be able to soon when >> kernel.org mirroring system catches them. > > There is no difference in optimizations except that here: > > for (i = 0; i < aiocb->aio_niov && count; ++i) { > > one of the two versions actually does "count && i < aiocb->aio_niov" due > to hashing vagaries. This is irrelevant anyway. Same inlining, same > loop optimization decisions, same everything else. So a GCC bug can be > ruled out, IMHO. > > The only difference, as someone already suspected, is the padding---the > sigset is placed between the top of the frame and the other variables, > which may hide an overrun. This is quite amazing for a function that > has no arrays, but still is the only evidence. > > I suggest trying to make the sigset_t static, since that generates > exactly the same code as the "nohang" case, and exactly the same stack > layout as the "hang" case. The next obvious step would be placing a > watchpoint somewhere.
Yes, but where? > Cheers, > > Paolo
