threads/79526: A memory leak in pthread_rwlock_init()

[Kimmo Mustonen]

>Number:         79526
>Category:       threads
>Synopsis:       A memory leak in pthread_rwlock_init()
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-threads
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Apr 04 12:40:12 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     Kimmo Mustonen
>Release:        FreeBSD 5.3-RELEASE-p6 i386
>Organization:
ROMmon Oy
>Environment:
System: FreeBSD tzimmopassive.rommon.fi 5.3-RELEASE-p6 FreeBSD 5.3-RELEASE-p6 #10: Thu Mar 31 14:43:05 EEST 2005 root at tzimmopassive.rommon.fi:/usr/src/sys/i386/compile/ROMMON-PROBE5 i386


	Pentium 4, FreeBSD 5.3, i386, pthread
>Description:
	Calling pthread_rwlock_init() leaks memory each time it is called.
        Example code
---8<---8<---
#include <pthread.h>

/* start using valgrind:
   valgrind --tool=memcheck -v --leak-check=yes --show-reachable=yes \
     --num-callers=100 ./leak_pthread_1
*/

int main(void)
{
  int i;
  pthread_rwlock_t lock;

  for (i = 0; i < 100; i++) {
    pthread_rwlock_init(&lock, NULL);
    pthread_rwlock_destroy(&lock);
  }

  return 0;
}
---8<---8<---
        and valgrind report
---8<---8<---
==801== 2012 bytes in 301 blocks are still reachable in loss record 1 of 1
==801==    at 0x3C033183: malloc (in /usr/local/lib/valgrind/vgpreload_memcheck.so)
==801==    by 0x3C03A8D0: (within /usr/local/lib/valgrind/libpthread.so.1)
==801==    by 0x3C03BF49: pthread_mutex_init (in /usr/local/lib/valgrind/libpthread.so.1)
==801==    by 0x3C03BFA9: pthread_mutex_lock (in /usr/local/lib/valgrind/libpthread.so.1)
==801==    by 0x3C03F174: (within /usr/local/lib/valgrind/libpthread.so.1)
==801==    by 0x3C03F2D9: pthread_rwlock_init (in /usr/local/lib/valgrind/libpthread.so.1)
==801==    by 0x8048609: main (leak_pthread_1.c:14)
==801== 
---8<---8<---
>How-To-Repeat:
	Run the example code using valgrind.
>Fix:
        Haven't looked at the sources, but probably easy to fix.
        I suppose pthread_rwlock_destroy() just does not free all the
        resources pthread_rwlock_init() allocates.

>Release-Note:
>Audit-Trail:
>Unformatted: