[schwidefsky@de.ibm.com] libc/1447: malloc fails if the executable is called via /lib/ld-2.1.1.so ./testexec

[Ulrich Drepper]

Andreas Jaeger <aj@suse.de> writes:

> We received the appended bug report about a different behaviour of
> malloc when a program is called via /lib/ld-linux.so.2.  On my systems
> I got:
> aj@arthur: 19:26:27 /tmp 
> $ ./ld-malloc 
> Malloc returned 8049790
> 
> aj@arthur: 19:26:29 /tmp 
> $ /lib/ld-linux.so.2 ./ld-malloc 
> Malloc returned 80014198
> 
> (compare the values - for Martin (?) Schwidefsky the second call
> failed completly - on my system (2.1.2 plus a number of patches) it's
> just a different value.
> 
> Is this a bug in the current sources?

This has nothing to do with the libc.  It's just how ther kernel
works.  It starts the heap right after the data section of the
program.  If the program is a pure executable it has a fixed load
address.  This is the normal case.  In case you run a dynamic object
the load address is a different and the heap ends up in a different
position and in this position there might be other objects blocking
the extension of the heap.  Not much one can do if the kernel decides
to do it this way.

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