On Tue, 2015-01-06 at 09:43 +0100, Jakub Jelinek wrote: > GCC trunk -fsanitize=undefined (in particular > -fsanitize=nonnull-attribute) > diagnoses it: > /tmp/mystring.cpp:103:26: runtime error: null pointer passed as > argument 2, which is declared to never be null
Unfortunately adding -fsanitize=undefined in GCC 4.9.2 doesn't notice this (in fact it actually causes the segfault to go away). I can try to build a trunk version for this test, I suppose. > LD_PRELOAD=libmemstomp.so detects it too. > > Calling memcpy (p, NULL, 0); is invalid according to C and C++ > standards, you need to guard it, e.g. with if (data) memcpy (p, data, > len1); > or if (len1) memcpy (p, data, len1); I'm on a Debian-based system and can't find a memstomp package so I grabbed git://fedorapeople.org/home/fedora/wcohen/public_git/memstomp and built it myself, but for some reason it doesn't fire in my environment: $ LD_PRELOAD=/home/psmith/src/memstomp/.libs/libmemstomp.so ./tst memstomp: 0.1.4 sucessfully initialized for process tst (pid 26438). Segmentation fault (core dumped) Even if I rebuild without -O3 it passes with no warnings. My GCC installation uses --sysroot to build against an older glibc, etc. so maybe that's causing some sort of issue... Seems like I have some work to do here to come up with a way to detect other failure situations like this.
