RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 835898 - Bug in DNS cache causes connections until restart of libcurl-using processes
Summary: Bug in DNS cache causes connections until restart of libcurl-using processes
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: curl
Version: 6.3
Hardware: All
OS: Linux
unspecified
medium
Target Milestone: rc
: ---
Assignee: Kamil Dudka
QA Contact: Stefan Kremen
URL:
Whiteboard:
Depends On:
Blocks: 835639
TreeView+ depends on / blocked
 
Reported: 2012-06-27 13:33 UTC by Kamil Dudka
Modified: 2015-07-22 05:42 UTC (History)
5 users (show)

Fixed In Version: curl-7.19.7-43.el6
Doc Type: Bug Fix
Doc Text:
Previously, libcurl did not properly refresh a DNS cache entry after it expired. Consequently, the expired cache entry kept being used despite a fresh DNS entry was available. This resulted in unnecessary connection failures. An upstream patch has been applied on libcurl source code to make sure that expired DNS cache entries are replaced by fresh ones. With the updated packages, such connection failures no longer happen.
Clone Of: 835639
Environment:
Last Closed: 2015-07-22 05:42:47 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2015:1254 0 normal SHIPPED_LIVE Moderate: curl security, bug fix, and enhancement update 2015-07-20 17:50:03 UTC

Description Kamil Dudka 2012-06-27 13:33:47 UTC 
+++ This bug was initially created as a clone of Bug #835639 +++

Description of problem:

A bug fixed in version 7.20 of libcurl is affecting a lot of my customers using software that depends on libcurl and maintains long-lived HTTP connection pools. Older versions had race conditions that "locked" stale DNS lookups in memory and prevented fresh DNS lookups. When IP addresses change, the library fails to detect the change and keeps accessing the stale address.

The bug fix is here:
http://sourceforge.net/tracker/index.php?func=detail&aid=2891595&group_id=976&atid=100976

I don't really guess you'll backport this, but I need to file this and get confirmation for my customers so that a decision on whether to junk use of RH-supplied libcurl will be the only recourse.

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

All versions < 7.20.0 of libcurl, including the one in RH5.

How reproducible:

It requires software that relies on connection pooling of libcurl handles and uses multiple threads with some load.

Steps to Reproduce:
1.Load test software using a particular destination name/address.
2.Change the DNS entry.
3.Observe new connections inheriting use of the old address.
  
Actual results:

The DNS change is not picked up.

Expected results:

New connections should see the change without restarting the process.

Additional info:

--- Additional comment from kdudka on 2012-06-27 15:30:23 CEST ---

upstream commit:

https://github.com/bagder/curl/commit/fb5f332
Comment 4 RHEL Program Management 2013-10-14 00:35:26 UTC 
This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated
in the current release, Red Hat is unable to address this
request at this time.

Red Hat invites you to ask your support representative to
propose this request, if appropriate, in the next release of
Red Hat Enterprise Linux.
Comment 14 errata-xmlrpc 2015-07-22 05:42:47 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/RHSA-2015-1254.html
Note You need to log in before you can comment on or make changes to this bug.