Re: svn commit: r352421 - head/stand/libsa
On Tue, Sep 17, 2019 at 12:05:26PM +0300, Toomas Soome wrote: > > > > On 17 Sep 2019, at 11:56, Konstantin Belousov wrote: > > > > On Mon, Sep 16, 2019 at 08:28:09PM +, Toomas Soome wrote: > >> Author: tsoome > >> Date: Mon Sep 16 20:28:08 2019 > >> New Revision: 352421 > >> URL: https://svnweb.freebsd.org/changeset/base/352421 > >> > >> Log: > >> loader: Malloc(0) should return NULL. > >> > >> We really should not allocate anything with size 0. > > Why ? This is quite unexpected from other environments, where > > malloc(0) returns unique object. > > > > Hiding bugs. And, we are not getting unique object, we are getting chunk of > memory with payload length of 0 and the memory content depends on if head and > tail guards are used - the chunk is with size at least MALLOCALIGN (16 or 64 > bytes) and the chunk is from random location of heap. > Yes, exactly, this is how all other mallocs behave. ___ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
Re: svn commit: r352421 - head/stand/libsa
> On 17 Sep 2019, at 11:56, Konstantin Belousov wrote: > > On Mon, Sep 16, 2019 at 08:28:09PM +, Toomas Soome wrote: >> Author: tsoome >> Date: Mon Sep 16 20:28:08 2019 >> New Revision: 352421 >> URL: https://svnweb.freebsd.org/changeset/base/352421 >> >> Log: >> loader: Malloc(0) should return NULL. >> >> We really should not allocate anything with size 0. > Why ? This is quite unexpected from other environments, where > malloc(0) returns unique object. > Hiding bugs. And, we are not getting unique object, we are getting chunk of memory with payload length of 0 and the memory content depends on if head and tail guards are used - the chunk is with size at least MALLOCALIGN (16 or 64 bytes) and the chunk is from random location of heap. rgds, toomas ___ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
Re: svn commit: r352421 - head/stand/libsa
On Mon, Sep 16, 2019 at 08:28:09PM +, Toomas Soome wrote:
> Author: tsoome
> Date: Mon Sep 16 20:28:08 2019
> New Revision: 352421
> URL: https://svnweb.freebsd.org/changeset/base/352421
>
> Log:
> loader: Malloc(0) should return NULL.
>
> We really should not allocate anything with size 0.
Why ? This is quite unexpected from other environments, where
malloc(0) returns unique object.
>
> Modified:
> head/stand/libsa/zalloc_malloc.c
>
> Modified: head/stand/libsa/zalloc_malloc.c
> ==
> --- head/stand/libsa/zalloc_malloc.c Mon Sep 16 20:26:53 2019
> (r352420)
> +++ head/stand/libsa/zalloc_malloc.c Mon Sep 16 20:28:08 2019
> (r352421)
> @@ -55,6 +55,9 @@ Malloc(size_t bytes, const char *file, int line)
> {
> Guard *res;
>
> +if (bytes == 0)
> + return (NULL);
> +
> #ifdef USEENDGUARD
> bytes += MALLOCALIGN + 1;
> #else
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svn commit: r352421 - head/stand/libsa
Author: tsoome
Date: Mon Sep 16 20:28:08 2019
New Revision: 352421
URL: https://svnweb.freebsd.org/changeset/base/352421
Log:
loader: Malloc(0) should return NULL.
We really should not allocate anything with size 0.
Modified:
head/stand/libsa/zalloc_malloc.c
Modified: head/stand/libsa/zalloc_malloc.c
==
--- head/stand/libsa/zalloc_malloc.cMon Sep 16 20:26:53 2019
(r352420)
+++ head/stand/libsa/zalloc_malloc.cMon Sep 16 20:28:08 2019
(r352421)
@@ -55,6 +55,9 @@ Malloc(size_t bytes, const char *file, int line)
{
Guard *res;
+if (bytes == 0)
+ return (NULL);
+
#ifdef USEENDGUARD
bytes += MALLOCALIGN + 1;
#else
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