run-parts segfaults with gcc 4.5.0

[Thierry Reding]

* walter harms wrote:
> 
> 
> Thierry Reding schrieb:
> > Hi,
> > 
> > After upgrading gcc to 4.5.0, I get segfaults when running the run-parts
> > applet. The segfault happens in bb_alphasort() during the calls to strcmp().
> > I debugged this and saw that the pointers passed into strcmp() were both
> > NULL. Apparently this comes from the act() function, which for some reason
> > overwrites the elements of the names array. Oddly enough, when I print that
> > same array at the end of each call to act() the segfault disappears.
> > 
> > FWIW, I came up with the following patch that fixes things, though it is
> > probably not the preferred way for busybox because it removes the names
> > variable from the global storage.
> > 
> 
> from gcc 4.5.0 changes:
> "There is a new optimization pass that attempts to change prototype of functions to avoid unused parameters, pass only relevant parts of
> structures and turn arguments passed by reference to arguments passed by value when possible. It is enabled by -O2 and above as well as -Os and
> can be manually invoked using the new command-line switch -fipa-sra. "
> 
> Since BB uses -Os as default, perhaps you can remove it and test again ?

Configuring busybox with CONFIG_DEBUG=y and CONFIG_DEBUG_PESSIMIZE=y fixes
the segfault. Setting those two variables seems the canonical way to tell
busybox to build with -O0.

Thierry
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