This is a known phenomenon. Valgrind (well, Memcheck, really) is more robust against applications that overwrite the ends/beginnings of heap blocks than the normal C malloc/free routines are. So if your application is doing such overwrites, that could explain the difference. What really would be a bug in Memcheck though is if it doesn't tell you about such overruns.
J On Monday, August 09, 2010, Christoffer Haglund wrote: > Hi, > > here's a little problem that has bothered me for a few days. I'm working > on isolating it further but thought there might be someone here who > might just know if this is expected behaviour of Valgrind, or if this is > something that should be reported as a bug. > > As the title says, I've managed to build an application that runs > correctly in Valgrind, but crashes with a segmentation fault when run > normally in a console. It's a normal C89 application, built with GCC on > a x86_64 machine. The culprit seems to be the auto-vectorization module > (which vectorizes some loops using SSE instructions). The segfault > occurs inside a loop that is reported as vectorized (with > -ftree-vectorizer-verbose=2), and the application runs as expected both > in Valgrind an in console when built with -fno-tree-vectorize. > > Now, I'm not saying that the compiler or code is flawless, but I had > expected the application to crash in Valgrind as well :-) > > The Valgrind version is reported as 3.6.0.SVN-Debian > GCC version 4.4.3 and 4.3.4 displays the mentioned behaviour, when > building with 4.1.3 the application works both in Valgrind and in the > console when vectorization is enabled. > > // Christoffer > _____________________________________________ > > CHRISTOFFER HAGLUND > Software Developer, Decuma > > Nuance Communications Sweden > Ole Römers väg 16 > SE-223 70 Lund > +46 (0) 46 286 53 43 Office > +46 (0) 709 59 63 06 Mobile > NUANCE.COM > The experience speaks for itself ™ ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Valgrind-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/valgrind-users
