This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: [PATCH] malloc.c fix for MALLOC_ALIGN_MASK tests.

From: Peter Bergner <bergner at vnet dot ibm dot com>
To: Ulrich Drepper <drepper at redhat dot com>
Cc: libc-alpha at sources dot redhat dot com
Date: Thu, 15 Sep 2005 13:21:15 -0500
Subject: Re: [PATCH] malloc.c fix for MALLOC_ALIGN_MASK tests.
References: <20050915153545.GA9653@otta.roc.mn.charter.com> <4329AFA1.8040306@redhat.com>

On Thu, 2005-09-15 at 10:30 -0700, Ulrich Drepper wrote:
> Look at the definition of mem2chunk.  It doesn't change the alignment.
> MALLOC_ALIGNMENT is 2*SIZE_SZ and just subtracts 2*SIZE_SZ.  So, state
> what your problem with the existing code is.

I'm sorry if I wasn't clear enough.  The problem occurs on arches that
define MALLOC_ALIGNMENT > 2*SIZE_SZ.  In that case, the chunk pointer
will not be aligned to MALLOC_ALIGNMENT since mem2chunk just subtracts
2*SIZE_SZ.  This means we cannot test whether our mem pointer is
properly aligned by testing its chunk pointer.  We need to test the
mem pointer directly.

Peter

Follow-Ups:
- Re: [PATCH] malloc.c fix for MALLOC_ALIGN_MASK tests.
  - From: Ulrich Drepper

References:
- [PATCH] malloc.c fix for MALLOC_ALIGN_MASK tests.
  - From: Peter Bergner
- Re: [PATCH] malloc.c fix for MALLOC_ALIGN_MASK tests.
  - From: Ulrich Drepper

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]