[FFmpeg-devel] Memory leak using bitstream filters with shared libs

[Uoti Urpala]

On Sun, 2008-03-09 at 09:26 -0400, Rich Felker wrote:
> On Sun, Mar 09, 2008 at 04:48:11AM +0200, Uoti Urpala wrote:
> > On Sat, 2008-03-08 at 19:23 -0500, Rich Felker wrote:
> > > It's actually an implementation bug since the C language requires that
> > > the addresses match. I suspect it's binutils doing something stupid
> > > due to -Bsymbolic. Anyway this sort of problem is common enough that
> > 
> > It's binutils doing what -Bsymbolic is documented to do - binding
> > references to global symbols to the definition within the shared
> > library. If the main program is compiled without -fPIC then functions
> > are normally bound to the main program's PLT entry (if one exists for
> > the function in question), and that's what other code will use.
> 
> This is a bug, plain and simple, in the linker. Binding _call_
> references is valid, but binding address-of references is not. The
> latter must be left either as a GOT lookup (if compiling PIC code) or
> a textrel (for non-PIC code).

Must be left as a GOT lookup - lookup of what? If you leave it the same
lookup as without -Bsymbolic then it could return a function completely
different from the one in the library. That would be completely
inconsistent (a direct call and an indirect call that gets the address
first calling different functions within the same block of code), and
would violate the documented behavior of -Bsymbolic (that it binds
references to the definition within the library).