* [PATCH] sysmalloc: Initialize previous size field of mmaped chunks
@ 2016-10-28 13:04 Florian Weimer
2016-10-28 14:13 ` Carlos O'Donell
0 siblings, 1 reply; 2+ messages in thread
From: Florian Weimer @ 2016-10-28 13:04 UTC (permalink / raw)
To: libc-alpha
With different encodings of the header, the previous zero initialization
may be insufficient and produce an invalid encoding.
2016-10-27 Florian Weimer <fweimer@redhat.com>
* malloc/malloc.c (sysmalloc): Initialize previous size field of
mmaped chunks.
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 186e174..72d22bd 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2306,6 +2306,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
else
{
p = (mchunkptr) mm;
+ set_prev_size (p, 0);
set_head (p, size | IS_MMAPPED);
}
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] sysmalloc: Initialize previous size field of mmaped chunks
2016-10-28 13:04 [PATCH] sysmalloc: Initialize previous size field of mmaped chunks Florian Weimer
@ 2016-10-28 14:13 ` Carlos O'Donell
0 siblings, 0 replies; 2+ messages in thread
From: Carlos O'Donell @ 2016-10-28 14:13 UTC (permalink / raw)
To: Florian Weimer, libc-alpha
On 10/28/2016 09:04 AM, Florian Weimer wrote:
> With different encodings of the header, the previous zero initialization
> may be insufficient and produce an invalid encoding.
>
> 2016-10-27 Florian Weimer <fweimer@redhat.com>
>
> * malloc/malloc.c (sysmalloc): Initialize previous size field of
> mmaped chunks.
>
> diff --git a/malloc/malloc.c b/malloc/malloc.c
> index 186e174..72d22bd 100644
> --- a/malloc/malloc.c
> +++ b/malloc/malloc.c
> @@ -2306,6 +2306,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
> else
> {
> p = (mchunkptr) mm;
> + set_prev_size (p, 0);
> set_head (p, size | IS_MMAPPED);
> }
>
Agreed. This looks good to me, and paves the way for the header
encodings to be non-zero.
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2016-10-28 13:04 [PATCH] sysmalloc: Initialize previous size field of mmaped chunks Florian Weimer
2016-10-28 14:13 ` Carlos O'Donell
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