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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.

Pavel, can you bring this up on samba-technical and CC me, please?

I've created an upstream bug for the issue.

Created attachment 781696 [details]
patch

Here is the patch which has been pushed upstream.

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".

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