Bug#684716: gcc-4.7: problem with local variables, works in gcc-4.6

[Fredrik Unger]

Package: gcc-4.7
Version: 4.7.1-6
Severity: normal

Dear Maintainer,


is a gcc bug, using the current gcc in sid (4.7.1-6).

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=678525

Included is gcc-bug.tar.gz that is a shortened version of the code
found in calendarserver :

While trying to get calendar server to run, I also ran into the Debian bug #678525. I created a simplified test case and could show that it http://trac.calendarserver.org/browser/CalendarServer/trunk/twext/python/sendmsg.c (Revision 8951)

To run the example :
tar xvfz gcc-bug.tar.gz
cd gcc-bug
make fail
python sender.py

produces the faulty output :
SCM_RIGHTS constant :  1
First call
level 1
type  1
2a 00 00 00 (4)
Second call
level 1
type  0
2a 00 00 00 (4)

This is using the current gcc in Debian sid : gcc (Debian 4.7.1-6) 4.7.1

make ok
python sender.py

produces the correct output :
SCM_RIGHTS constant :  1
First call
level 1
type  1
2a 00 00 00 (4)
Second call
level 1
type  1
2a 00 00 00 (4)

This using current gcc-4.6 in Debian sid : gcc-4.6 (Debian 4.6.3-8) 4.6.3

The first and the second call should produce the same output but
in the faulty run type becomes 0.
Due to the 0, the linux kernel check in
http://lxr.linux.no/linux+v3.2/net/core/scm.c#L159
fails, and gives the Invalid Argument error in the Debian bug #678525.

If more information is needed let me know.

Thank you,

Fredrik Unger

-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.2.0-3-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages gcc-4.7 depends on:
ii  binutils      2.22-7.1
ii  cpp-4.7       4.7.1-6
ii  gcc-4.7-base  4.7.1-6
ii  libc6         2.13-35
ii  libgcc1       1:4.7.1-6
ii  libgmp10      2:5.0.5+dfsg-2
ii  libgomp1      4.7.1-6
ii  libitm1       4.7.1-6
ii  libmpc2       0.9-4
ii  libmpfr4      3.1.0-5
ii  libquadmath0  4.7.1-6
ii  zlib1g        1:1.2.7.dfsg-13

Versions of packages gcc-4.7 recommends:
ii  libc6-dev  2.13-35

Versions of packages gcc-4.7 suggests:
pn  binutils-gold        <none>
pn  gcc-4.7-doc          <none>
pn  gcc-4.7-locales      <none>
pn  gcc-4.7-multilib     <none>
pn  libgcc1-dbg          <none>
pn  libgomp1-dbg         <none>
pn  libitm1-dbg          <none>
pn  libmudflap0-4.7-dev  <none>
pn  libmudflap0-dbg      <none>
pn  libquadmath0-dbg     <none>

-- no debconf information

gcc-bug.tar.gz
Description: application/gzip