Package segfaults when built with -O2 but not with -O0

[Ralf Corsepius]

On 12/01/2011 11:23 AM, Paul Howarth wrote:
> Ralf,
>
> On 11/18/2011 05:53 PM, Ralf Corsepius wrote:
>> On 11/18/2011 05:32 PM, Paul Howarth wrote:
>>> It already builds with -Wall and there are no warnings:
>> This doesn't mean much.
>>
>> Adding a couple of more agressive options, this is what happens to pptp:
>>

> What were the "couple of more agressive options" you used,

This is what I did (rebased against today's git):

diff --git a/pptp.spec b/pptp.spec
index 289dd08..78e36ca 100644
--- a/pptp.spec
+++ b/pptp.spec
@@ -86,7 +86,7 @@ tunnels.
  perl -pi -e 's/install -o root -m 555 pptp/install -m 755 pptp/;' Makefile

  %build
-make %{?_smp_mflags} CFLAGS="-Wall %{optflags}" IP=/sbin/ip
+make %{?_smp_mflags} CFLAGS="-Wall %{optflags} -Wextra 
-Wstrict-aliasing -Wnested-externs -Wstrict-prototypes" IP=/sbin/ip

  %install
  rm -rf %{buildroot}


> and which
> distro?

Local rawhide mock.

The result I posted was extracted from a "fedpkg mockbuild"'s build.log 
in a local mock on fedora-16/x86_64.


> I've tried "-Wall -Wextra" and still can't provoke the strict
> aliasing warning locally.
-Wstrict-aliasing is responsible for this warning.

Today's version looks like this:

# grep warning: results_pptp/1.7.2/13.fc17/build.log  | grep punned
pptp_gre.c:92:29: warning: dereferencing type-punned pointer might break 
strict-aliasing rules [-Wstrict-aliasing]
pptp_gre.c:99:28: warning: dereferencing type-punned pointer might break 
strict-aliasing rules [-Wstrict-aliasing]
pptp_callmgr.c:202:48: warning: dereferencing type-punned pointer might 
break strict-aliasing rules [-Wstrict-aliasing]
pptp_callmgr.c:325:29: warning: dereferencing type-punned pointer might 
break strict-aliasing rules [-Wstrict-aliasing]
pptp_callmgr.c:330:28: warning: dereferencing type-punned pointer might 
break strict-aliasing rules [-Wstrict-aliasing]
pptp_callmgr.c:358:25: warning: dereferencing type-punned pointer might 
break strict-aliasing rules [-Wstrict-aliasing]
pptp.c:459:33: warning: dereferencing type-punned pointer might break 
strict-aliasing rules [-Wstrict-aliasing]

Ralf