Date: Tue, 25 Jan 2011 14:47:54 GMT From: Sebastian Huber <sebastian.huber@embedded-brains.de> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/154287: Avoid malloc(0) implementation dependency in device_get_children() Message-ID: <201101251447.p0PElsSf073901@red.freebsd.org> Resent-Message-ID: <201101251450.p0PEo81W095876@freefall.freebsd.org>
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>Number: 154287
>Category: kern
>Synopsis: Avoid malloc(0) implementation dependency in device_get_children()
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: change-request
>Submitter-Id: current-users
>Arrival-Date: Tue Jan 25 14:50:07 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator: Sebastian Huber
>Release: 9-current
>Organization:
embedded brains GmbH
>Environment:
>Description:
The device_get_children() implementation of the device(9) API depends on a particular malloc(0) behavior. This makes it less portable to other operating systems. The following patch avoids a malloc(0).
>How-To-Repeat:
>Fix:
Index: kern/subr_bus.c
===================================================================
--- kern/subr_bus.c (revision 216297)
+++ kern/subr_bus.c (working copy)
@@ -2090,14 +2090,19 @@
count++;
}
- list = malloc(count * sizeof(device_t), M_TEMP, M_NOWAIT|M_ZERO);
- if (!list)
- return (ENOMEM);
+ if (count) {
+ list = malloc(count * sizeof(device_t), M_TEMP,
+ M_NOWAIT|M_ZERO);
+ if (!list)
+ return (ENOMEM);
- count = 0;
- TAILQ_FOREACH(child, &dev->children, link) {
- list[count] = child;
- count++;
+ count = 0;
+ TAILQ_FOREACH(child, &dev->children, link) {
+ list[count] = child;
+ count++;
+ }
+ } else {
+ list = NULL;
}
*devlistp = list;
>Release-Note:
>Audit-Trail:
>Unformatted:
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