Date: Sun, 15 Feb 2004 01:20:26 +0100 (CET) From: Stefan Farfeleder <stefan@fafoe.narf.at> To: FreeBSD-gnats-submit@FreeBSD.org Cc: marcel@FreeBSD.org Subject: bin/62859: [patch] malloc(0) fails to call malloc_init() Message-ID: <20040215002026.0939A32A@wombat.fafoe.narf.at> Resent-Message-ID: <200402150030.i1F0UHYx038517@freefall.freebsd.org>
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>Number: 62859
>Category: bin
>Synopsis: [patch] malloc(0) fails to call malloc_init()
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sat Feb 14 16:30:17 PST 2004
>Closed-Date:
>Last-Modified:
>Originator: Stefan Farfeleder
>Release: FreeBSD 5.2-CURRENT i386
>Organization:
>Environment:
System: FreeBSD wombat.fafoe.narf.at 5.2-CURRENT FreeBSD 5.2-CURRENT #13: Thu Feb 5 23:10:05 CET 2004 stefan@wombat.fafoe.narf.at:/usr/home/stefan/freebsd/obj/usr/home/stefan/freebsd/src/sys/WOMBAT i386
>Description:
The function malloc_init() parses malloc()'s options from /etc/malloc.conf,
MALLOC_OPTIONS and _malloc_options. It's the function imalloc() that calls
malloc_init(), and the former one is not called on malloc(0). This isn't a
problem per se, but the v/V flag controls the behaviour of malloc(0) and so it
never returns a null pointer until malloc() is called with a positived size.
>How-To-Repeat:
This program demonstrates that the V flag is ignored:
#include <stdio.h>
#include <stdlib.h>
int
main(void)
{
_malloc_options = "V";
printf("malloc(0) = %p\n", malloc(0));
return (0);
}
>Fix:
This moves the malloc_init() calls into malloc() and realloc().
--- malloc.c.diff begins here ---
Index: src/lib/libc/stdlib/malloc.c
===================================================================
RCS file: /usr/home/ncvs/src/lib/libc/stdlib/malloc.c,v
retrieving revision 1.84
diff -I.svn -u -r1.84 malloc.c
--- src/lib/libc/stdlib/malloc.c 28 Nov 2003 18:03:22 -0000 1.84
+++ src/lib/libc/stdlib/malloc.c 14 Feb 2004 23:42:47 -0000
@@ -736,9 +736,6 @@
{
void *result;
- if (!malloc_started)
- malloc_init();
-
if (suicide)
abort();
@@ -1111,6 +1108,9 @@
{
void *r;
+ if (!malloc_started)
+ malloc_init();
+
_MALLOC_LOCK();
malloc_func = " in malloc():";
if (malloc_active++) {
@@ -1161,6 +1161,9 @@
{
void *r;
int err = 0;
+
+ if (!malloc_started)
+ malloc_init();
_MALLOC_LOCK();
malloc_func = " in realloc():";
--- malloc.c.diff ends here ---
>Release-Note:
>Audit-Trail:
>Unformatted:
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