Elia Pinto <gitter.spi...@gmail.com> writes: >> - That "165" thing I mentioned earlier. > > Thank you so much for the comments, that's fine. A single > consideration for MALLOC_PERTURB. > > You can use any value between 1..255 for MALLOC_PERTURB_ > That chooses the byte that glibc will use to memset all freed buffers. > In general it is defined as > > export MALLOC_PERTURB_=$(($RANDOM % 255 + 1)) > > (as drepper pointed out http://udrepper.livejournal.com/11429.html)
Drepper never recommends RANDOM there. > Using a random value is slightly better than using a fixed one > in case your fixed value is someday just the right/wrong value to mask > a problem. Quite the contrary. When you use a fixed pattern, it is easy which other pieces of memory has uninitailized contents. When you use a random value, you sometimes get an error and sometimes the test mysteriously pass, which does not help debugging. openSUSE folks seem to use a fixed value for this exact reason of repeatability of tests. http://jaegerandi.blogspot.com/2012/01/finding-subtile-malloc-bugs.html > So OK per the original expression? No. I am not convinced 165 is the perfect value, but I am fairly certain any fixed value is better than using a random to deliberately worsen repeatability of the tests. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
