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Bug 1192621

Summary:	gethostbyname_r hangs forever
Product:	Red Hat Enterprise Linux 6	Reporter:	Eric Newton <eric.newton>
Component:	glibc	Assignee:	Florian Weimer <fweimer>
Status:	CLOSED ERRATA	QA Contact:	Arjun Shankar <ashankar>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	6.8	CC:	ashankar, codonell, ctubbsii, fweimer, mnewsome, pfrankli
Target Milestone:	rc	Keywords:	Patch
Target Release:	---
Hardware:	All
OS:	Unspecified
Whiteboard:
Fixed In Version:	glibc-2.12-1.177.el6	Doc Type:	Bug Fix
Doc Text:	The DNS stub resolver, when reordering of resource records has been enabled, could hang indefinitely while processing the first few DNS responses. The faulty lock management has been corrected and the hang no longer occurs.	Story Points:	---
Clone Of:
Clones:	1288613 (view as bug list)		Environment:
Last Closed:	2016-05-10 21:25:59 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1172231, 1271375

Description Eric Newton 2015-02-13 21:00:48 UTC

Please see https://sourceware.org/bugzilla/show_bug.cgi?id=17977

Comment 3 Christopher Tubbs 2015-06-25 18:23:54 UTC

This was fixed in upstream master branch. Not sure what their release schedule is, but might be worth pulling in the patch asap, so it doesn't bite any more users.

Comment 5 Carlos O'Donell 2015-08-25 16:27:52 UTC

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b57525f1a376149840f740a31535681c07152ba4

commit b57525f1a376149840f740a31535681c07152ba4
Author: Dmitry V. Levin <ldv>
Date:   Thu Jun 18 21:40:46 2015 +0000

    Fix potential hanging of gethostbyaddr_r/gethostbyname_r
    
    When "reorder" resolver option is enabled, threads of a multi-threaded process
    could hang in gethostbyaddr_r, gethostbyname_r, or gethostbyname2_r.
    
    Due to a trivial bug in _res_hconf_reorder_addrs, simultaneous
    invocations of this function in a multi-threaded process could result to
    _res_hconf_reorder_addrs returning without releasing the lock it holds,
    causing other threads to block indefinitely while waiting for the lock
    that is not going to be released.
    
    [BZ #17977]
    * resolv/res_hconf.c (_res_hconf_reorder_addrs): Fix unlocking
    when initializing interface list, based on the bug analysis
    and the patch proposed by Eric Newton.
    * resolv/tst-res_hconf_reorder.c: New test.
    * resolv/Makefile [$(have-thread-library) = yes] (tests): Add
    tst-res_hconf_reorder.
    ($(objpfx)tst-res_hconf_reorder): Depend on $(libdl)
    and $(shared-thread-library).
    (tst-res_hconf_reorder-ENV): New variable.

Comment 14 errata-xmlrpc 2016-05-10 21:25:59 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-0834.html