On Tue, Jun 10, 2014 at 10:46 AM, Linus Torvalds <torva...@linux-foundation.org> wrote: > On Tue, Jun 10, 2014 at 6:23 AM, Jiri Kosina <jkos...@suse.cz> wrote: >> We have been chasing a memory corruption bug, which turned out to be >> caused by very old gcc (4.3.4), which happily turned conditional load into >> a non-conditional one, and that broke correctness (the condition was met >> only if lock was held) and corrupted memory. > > Just out of interest, can you point to the particular kernel code that > caused this? I think that's more interesting than the example program > you show - which I'm sure is really nice for gcc developers as an > example, but from a kernel standpoint I think it's more important to > show the particular problems this caused for the kernel? >
Jiri, is there a workaround for compilers that don't support '--param allow-store-data-races=0'? For example: $ gcc-4.5 -O2 -o cond_store cond_store.c && ./cond_store Segmentation fault (core dumped) $ gcc-4.5 -O2 --param allow-store-data-races=0 -o cond_store cond_store.c && ./cond_store cc1: error: invalid parameter ‘allow-store-data-races’ $ gcc-4.5 -v Using built-in specs. COLLECT_GCC=gcc-4.5 COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.5.4/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --libdir=/usr/lib --libexecdir=/usr/lib --program-suffix=-4.5 --enable-shared --enable-languages=c,c++,fortran,objc,obj-c++ --enable-__cxa_atexit --disable-libstdcxx-pch --disable-multilib --disable-libgomp --disable-libmudflap --disable-libssp --enable-clocale=gnu --with-tune=generic --with-cloog --with-ppl --with-system-zlib Thread model: posix gcc version 4.5.4 (GCC) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
