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Bug 978962

Summary: tevent_loop_wait() never finishes
Product: Red Hat Enterprise Linux 6 Reporter: Pavel Březina <pbrezina>
Component: libteventAssignee: Jakub Hrozek <jhrozek>
Status: CLOSED ERRATA QA Contact: Kaushik Banerjee <kbanerje>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 6.4CC: apeetham, asn, jgalipea
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: libtevent-0.9.18-3.el6 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
: 994015 (view as bug list) Environment:
Last Closed: 2013-11-21 05:42:32 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: 994015    
Attachments:
Description Flags
reproducer
none
patch none

Description Pavel Březina 2013-06-27 11:50:19 UTC
Created attachment 766074 [details]
reproducer

Description of problem:
If a signal handler is registered and unregistered later, tevent_loop_wait() never finishes.

Version-Release number of selected component (if applicable):
libtevent-0.9.17-1.el6.x86_64

How reproducible:
Always.

Steps to Reproduce:
Reproducer is attached.
1. gcc -ltalloc -ltevent tevent_loop.c
2. ./a.out

Actual results:
The program never gets out of tevent_loop_wait().
"We got through the loop! OK" is never printed.

Expected results:
The program gets through tevent_loop_wait().
"We got through the loop! OK" is printed.

Additional info:
This is because tevent internally registers its own signal handler "sig_pipe_handler". This handler is never removed, which causes program to stuck in tevent_loop_wait() even if there are no custom handlers registered.

Comment 2 Jakub Hrozek 2013-06-27 14:41:28 UTC
Pavel, can you bring this up on samba-technical and CC me, please?

Comment 4 Andreas Schneider 2013-07-11 13:02:11 UTC
I've created an upstream bug for the issue.

Comment 5 Andreas Schneider 2013-08-01 18:16:18 UTC
Created attachment 781696 [details]
patch

Here is the patch which has been pushed upstream.

Comment 7 Amith 2013-10-16 08:32:43 UTC
Verified the bug on libtevent Version: libtevent-0.9.18-3.el6.x86_64

Steps followed during verification:

1. Copied the reproducer "tevent_loop.c" onto the client system.
2. # gcc -ltalloc -ltevent tevent_loop.c

3. Execute the reproducer program:
 
[root@rhel-65 bkup]# ./a.out 
Registering signal handler...
Unregistering signal handler...
Entering tevent loop...
We got through the loop! OK

As expected, the program gets through tevent_loop_wait(), and prints "We got through the loop! OK".

Comment 9 errata-xmlrpc 2013-11-21 05:42:32 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.

http://rhn.redhat.com/errata/RHBA-2013-1552.html