Bug 432721

Summary:	pthread_create leaks memory
Product:	Red Hat Enterprise Linux 4	Reporter:	Julien Pierre <julien.pierre.boogz>
Component:	glibc	Assignee:	Jakub Jelinek <jakub>
Status:	CLOSED NOTABUG	QA Contact:	Brian Brock <bbrock>
Severity:	high	Docs Contact:
Priority:	low
Version:	4.0	CC:	kengert, wtc
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2008-02-14 08:19:19 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Julien Pierre 2008-02-13 23:57:47 UTC

Description of problem:

Calls to pthread_create cause the following leak :

==4020== 204 bytes in 3 blocks are possibly lost in loss record 5 of 7
==4020==    at 0x442AC82: calloc (vg_replace_malloc.c:279)
==4020==    by 0x410EDEB: _dl_allocate_tls (in /lib/ld-2.3.2.so)
==4020==    by 0x45C826D: allocate_stack (in /lib/tls/libpthread-0.60.so)
==4020==    by 0x45C7EF7: pthread_create@@GLIBC_2.1 (in
/lib/tls/libpthread-0.60.so)

Version-Release number of selected component (if applicable):

We saw this on both RHEL 3 and RHEL 4, with glibc

Our RHEL4 box has
libc-2.3.4-2.25

And RHEL3 :
glibc-2.3.2-95.37

See https://bugzilla.mozilla.org/show_bug.cgi?id=367376 for more details.

Comment 1 Jakub Jelinek 2008-02-14 08:19:19 UTC

What makes you think this is a leak?  NPTL has a cache of thread stacks prepared
for reuse, so the memory is still accessible.  If you 1000 times pthread_create
followed by 1000 pthread_join calls, you won't get 1000 unfreed blocks.