[ruby-core:22682] Re: MBARI8 patch fixes bugs caused by incorrect volatile variable declarations

I knew I was forgetting something on the original mail:

I am seeing the segfault with stack clearing set to both default level and
0x0.
I am not seeing the segfault with MRI
The segfault is in our test suite which does some app setup and config,
which is way I am working on whittling it down to something smaller and
eliminate dependencies on our custom code.
Our app does use a third party C library that we do not have source for, but
I'm not sure if its loaded at the point of the error.

uname -a
Linux mking-3.dev.xxxx.com 2.6.15-51-server #1 SMP Thu Dec 6 21:37:18 UTC
2007 i686 GNU/Linux

gcc -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++,java,f95,objc,ada,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--program-suffix=-4.0 --enable-__cxa_atexit --enable-clocale=gnu
--enable-libstdcxx-debug --enable-java-awt=gtk-default --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-4.0-1.4.2.0/jre --enable-mpfr
--disable-werror --with-tune=pentium4 --enable-checking=release
i486-linux-gnu
Thread model: posix
gcc version 4.0.3 (Ubuntu 4.0.3-1ubuntu5)

ruby --version
ruby 1.8.6 (2009-3-1 MBARI 8B/0x0 on patchlevel 287) [i686-linux]

configure options
--enable-readline \
--enable-zlib \
--enable-mbari-api \
--with-wipe-sites=0x0 \
CFLAGS="-O0 -g"

On Wed, Mar 4, 2009 at 5:01 PM, Brent Roman <[e-mail]> wrote:

>
> Michael,
>
> Could you send me the output of
> $ uname -a
> $ gcc -v
> and the configure cmd used to build with CFLAGS, etc.
> ?
>
> Ruby's conservative GC reads unintialized memory.  That can't be helped.
> When I was heavy into valgrind, I created a suppression file to
> help it recognize and suppress reporting these errors.
>
> http://www.faqs.org/docs/Linux-HOWTO/Valgrind-HOWTO.html
>
> Use --gen-suppressions=yes to automatically create suppression
> records, then tweak them by hand to make them less specific.
>
> The only valgrind reports here that concern me a bit are the invalid reads.
> I'd have to look into these a bit deeper to be sure.
>
> By the way, is it the ruby test suite or your app's that segfaults in
> drb.rb?
> (or both?)  If only in your app, is it using any non-standard 'C'
> extensions?
>
> I'm assuming you've already verified that the segfaults don't also occur
> with unpatched Ruby.
> One more thing to try is to set STACK_WIPES_SITES to 0x0000.
>
> - brent
>
>
> Michael King-2 wrote:
> >
> > I am having an issue with the MBARI patches. In our app the test suite
> has
> > a
> > segfault at line 1413 in drb.rb. I am compiling Ruby on Ubuntu 6.06,
> > 32bit,
> > GCC 4.0.3. The segfault shows up when compiling at O2 and O0(zero). At
> the
> > moment I am trying to whittle down the test to give you something
> > reproducible.
> >
> > I the meantime, I ran valgrind and the results showed an improvement over
> > MRI. I have attached the results of that valgrind run, the errors were of
> > 4
> > basic types and were in linked libraries or gc.c:
> > Conditional jump or move depends on uninitialised value(s)
> > Use of uninitialised value of size 4
> > Invalid read of size
> > Address 0x#{address} is #{X} bytes inside a block of size #{X+2} alloc'd
> >
> > - Michael
> >
> >
>
> --
> View this message in context:
> http://www.nabble.com/MBARI8-patch-fixes-bugs-caused-by-incorrect-volatile-variable-declarations-tp22259357p22341606.html
> Sent from the ruby-core mailing list archive at Nabble.com.
>
>
>