malloc() problem on sysv386

[Tom Armistead]

In article <1991May23.094026.18969 at hollie.rdg.dec.com> moore at forty2.enet.dec.com (Paul Moore) writes:
>I've recently had this error occuring when malloc is called running an
>application on ISC SVR3.2 (observed from the sdb debugger):
>
>   memory fault (11) (sig 11)
>
>The man page for signal(3) indicates that this is a segmentation violation. 
>
>The problem only occurs when malloc() had been previously called in the code
>execution path; it doesn't appear when this code path isn't executed.
>
>The problem doesn't appear at all when I run the very same application on
>Ultrix.
>
>Any ideas, anyone?
>
>- Paul

These type of errors are usually caused by 1 of 2 things (or both).
  1. Freeing an un-malloc'd or already-free'd pointer.
  2. Overwriting the end of a malloc'd area.

In either case, it's usually on the next malloc() call that you get the core
dump (sometimes *several* malloc's later).

And these types of errors are generally a bitch to find...

Tom
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