Date: Thu, 11 May 2000 13:04:19 -0400 From: James FitzGibbon <james@targetnet.com> To: FreeBSD-gnats-submit@freebsd.org Subject: misc/18504: Memory leak in uthread_set_name_np Message-ID: <E12pwNn-0000Bl-00@mail.targetnet.com>
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>Number: 18504
>Category: misc
>Synopsis: pthread_set_name_np leaks memory
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu May 11 10:10:00 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator: James FitzGibbon
>Release: FreeBSD 3.2-RELEASE i386 (but still present in -current)
>Organization:
Targetnet.com Inc.
>Environment:
Any pthread program using the non-portable pthread_set_name_np function
(defined in /usr/include/pthread_private.h)
>Description:
struct pthread contains a member variable "char *name", which is used to
store the name of the thread. pthread_set_name_np is used to set this
member variable. There are several problems:
- pthread_create does not set the member to a known valid state (NULL)
- pthread_set_name_np does not check if the member is NULL before assigning
the return value of strdup to it.
- the garbage collector thread (lib/libc_r/uthread/uthread_gc.c) does not
free the memory used by the member, if any.
>How-To-Repeat:
Call pthread_set_name_np multiple times. The program will leak as many
bytes as are passed as to pthread_set_name_np.
>Fix:
The following patch addresses the above three issues.
diff -ru /usr/src/lib/libc_r/uthread/uthread_create.c uthread/uthread_create.c
--- /usr/src/lib/libc_r/uthread/uthread_create.c Thu Mar 23 02:06:40 2000
+++ uthread/uthread_create.c Thu May 11 12:47:49 2000
@@ -164,6 +164,7 @@
new_thread->slice_usec = -1;
new_thread->sig_saved = 0;
new_thread->stack = stack;
+ new_thread->name = NULL;
new_thread->start_routine = start_routine;
new_thread->arg = arg;
diff -ru /usr/src/lib/libc_r/uthread/uthread_gc.c uthread/uthread_gc.c
--- /usr/src/lib/libc_r/uthread/uthread_gc.c Tue Dec 28 13:13:02 1999
+++ uthread/uthread_gc.c Thu May 11 12:53:15 2000
@@ -243,6 +243,13 @@
free(p_stack);
if (pthread_cln != NULL)
/*
+ Free the memory allocated for the thread
+ name, if any
+ /*
+ if( pthread_cln.name != NULL ) {
+ free(pthread_cln.name);
+ }
+ /*
* Free the memory allocated for the thread
* structure.
*/
diff -ru /usr/src/lib/libc_r/uthread/uthread_info.c uthread/uthread_info.c
--- /usr/src/lib/libc_r/uthread/uthread_info.c Wed Sep 29 11:18:38 1999
+++ uthread/uthread_info.c Thu May 11 12:48:32 2000
@@ -305,6 +305,10 @@
{
/* Check if the caller has specified a valid thread: */
if (thread != NULL && thread->magic == PTHREAD_MAGIC)
+ /* Free the existing name, if any */
+ if( thread->name != NULL ) {
+ free(thread_name);
+ }
thread->name = strdup(name);
return;
}
The patch is relative to RELENG_4, but should apply to -current as well.
After the standard wait period, a MFC to RELENG_4 (and RELENG_3 if possible)
would be appreciated.
>Release-Note:
>Audit-Trail:
>Unformatted:
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