[Gc] Duplicate large block deallocation

Boehm, Hans hans.boehm at hp.com
Fri Apr 23 16:02:37 PDT 2004

The message is complaining that the GC-internal large block
allocator is being called to deallocate a block that was
already available.

The possible causes for this are:

1) Duplicate explicit deallocation by client code.  (In the case
of C++, the call could easily be compiler generated.)

2) A collector bug.

This is the first complaint I've heard along these lines in a long time,
so my immediate inclination would be to go with (1), unless something
like gctest also exhibits the problem in your environment.

This message is generated around line 793 in allchblk.c.  A stack trace
at that point should tell you where the object is being deallocated a
second time.  That may or may not be enough information
to track this down.

A likely workaround is to remove explicit deallocations.


-----Original Message-----
From: gc-bounces at napali.hpl.hp.com [mailto:gc-bounces at napali.hpl.hp.com]On Behalf Of Miguel Guinada
Sent: Friday, April 23, 2004 10:20 AM
To: gc at napali.hpl.hp.com
Subject: [Gc] Duplicate large block deallocation 

I’m using de Garbage Collector for one month (with Borland C++Builder 5) a recently 10% of the time I execute my code I have an AccessViolation and gc.log gives the message:
Duplicate large block deallocation of XXXXX
Can anyone give me a clue of what’s happening!
Thanks for the time

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