On Tue, 2011-05-17 at 20:39 +0200, Svante Signell wrote: > On Tue, 2011-05-17 at 19:47 +0200, Thomas Schwinge wrote: > > Apparently there's something going very wrong for us, for some of the > > hardening flags, such that GDB gets confused, SEGFAULTs arise, and all > > what we've seen. Svante, sorry, I really didn't expect something like > > that... (Welcome to the wonderful world of debugging.) The reason I > > don't know yet. Perhaps some GCC specs oddity. Or something in glibc/in > > the dynamic linker. >
Yes, something is definitely different compared to other architectures since the builds work there. > > Next step, II: Figure out what's going wrong. Svante, interested? I > > would begin as follows. > > Ill take a look. Thanks for discovering this mess. I should have seen it > too :-( I found out which environment variable triggers the segfault by compiling exim4-4.76 several times: I tried with simpler ones without success: 1) A small file trivial.c at the debian wiki): 2) A small test example at: http://gcc.gnu.org/ml/gcc-bugs/2008-04/msg01075.html Next step would be to find out the differences in configuration for gcc, glibc, dynamic linker etc causing the segfault. Main environment variable: DEB_BUILD_HARDENING=1 Sub-variables: export DEB_BUILD_HARDENING_FORMAT=1 : NO export DEB_BUILD_HARDENING_FORTIFY=1 : YES, both with -O1 and -O2! export DEB_BUILD_HARDENING_STACKPROTECTOR=1: NO export DEB_BUILD_HARDENING_PIE=0 : NO export DEB_BUILD_HARDENING_RELRO=0 : NO export DEB_BUILD_HARDENING_BINDNOW=0 : NO >From http://wiki.debian.org/Hardening: Code compiled with -Werror and using memcpy/strcpy with qualifier overrides will fail with FORTIFY enabled. See https://launchpad.net/bugs/217481 More info from the gcc patch introducing hardening, see http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
