assertion: z->z_Magic == ZALLOC_SLAB_MAGIC in _slabfree

Peter Avalos peter at
Thu Mar 24 03:30:58 PDT 2011

On Thu, Mar 24, 2011 at 10:00:59AM +0100, Magliano Andre' wrote:
> Hi Peter,
> it seems to me (if i don't see ghosts) that the problem is at:
> #6 0x2ac85455 in operator delete (ptr=0x0)
> but if i look in
> /usr/src/contrib/gcc-4.4/libstdc++-v3/libsupc++/
> i see:
> operator delete(void* ptr) throw ()
> {
>   if (ptr)
>     std::free(ptr);
> }
> i.e. checking against NULL pointer is done, so it should'nt happen.

I'm not sure what's going on there...

#5  0x2821bd7b in free (ptr=0x2abd81bc) at /usr/src/lib/libc/../libc/stdlib/nmalloc.c:774
#6  0x2ac93455 in operator delete (ptr=0x0)
    at /usr/src/gnu/lib/gcc44/libstdc++/../../../usr.bin/cc44/cc_tools/../../../../contrib/gcc-4.4/libstdc++-v3/libsupc++/
#7  0x2ac27385 in __gnu_cxx::new_allocator<char>::deallocate (this=0x2abd81bc, __a=...) at /usr/obj/usr/src/world_i386/usr/include/c++/4.4/ext/new_allocator.h:95

Notice that in #7, you have this=0x2abd81bc and in #5 you have
ptr=0x2abd81bc.  Not sure how to explain that...

> What happens if you recompile vlc with gcc 4.4?

I can't compile vlc any more.  It fails during the build.  The 2nd
backtrace is when I attempt to build vlc (it tries to run some program
as part of the build that winds up hitting the assertion).

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