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Bug 661748

Summary: [6.0] When strace is used, waitpid() without __WCLONE or __WALL option waits for children created by clone().
Product: Red Hat Enterprise Linux 6 Reporter: Alan Matsuoka <alanm>
Component: straceAssignee: Andreas Schwab <schwab>
Status: CLOSED ERRATA QA Contact: qe-baseos-tools-bugs
Severity: urgent Docs Contact:
Priority: urgent    
Version: 6.0CC: cww, ebachalo, fnadge, jwest, makc, mnowak, moshiro, myamazak, pmuller, rbiba, roland, snagar, syeghiay
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: strace-4.5.19-1.8.el6 Doc Type: Bug Fix
Doc Text:
Cause: When strace is used, waitpid without __WCLONE or __WALL option waits for children created by clone Consequence: Fix: don't suspend process calling waitpid Result: don't suspend process calling waitpid
Story Points: ---
Clone Of:
: 663547 (view as bug list) Environment:
Last Closed: 2011-03-10 07:45:25 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:
Bug Depends On:    
Bug Blocks: 662543, 663547, 672767    
Attachments:
Description Flags
reproducer
none
sosreport-rhel60GA-Intel64-20101101093400-e832.tar.xz
none
test which uses clone none

Description Alan Matsuoka 2010-12-09 15:20:04 UTC
Created attachment 467767 [details]
reproducer

Description of Problem:
Usually, waitpid() waits for children created by clone() only when
__WCLONE or __WALL option is present.
However, when strace is used, waitpid() without __WCLONE or __WALL option
waits for children created by clone().

Version-Release number of selected component:
Red Hat Enterprise Linux Version Number: 6.0
Release Number: GA
Architecture: x86_64
Kernel Version: 2.6.32-71.el6.x86_64
Related Package Version: strace-4.5.19-1.6.el6.x86_64
Related Middleware/Application: none

Drivers or hardware or architecture dependency:
none

How reproducible:
Always

Step to Reproduce:
I attach a reproducer: testpro.c

1. Compile the above target program (testpro.c):
# gcc -g -o testpro testpro.c

2. Execute test program with strace command:
# strace -f -o log ./testpro

Actual Results:
Parent process suspends.

Expected Results:
Parent process does not suspend.

Summary of actions taken to resolve issue: none

Location of diagnostic data: none

Hardware configuration:
Model: PRIMERGY TX300S4
CPU Info: Intel Xeon CPU 1.86GHz x 2
Memory Info: 4GB
Hardware Component Information: none
Configuration Info: none


Business Impact:
Middleware and/or application programmer cannot debug or investigate
their programs.

Target Release: RHEL6.1
Errata Request: async errata for 6.0.z
Hotfix Request: No


Additional Info:
This issue happens to RHEL5.6alpha too. I will make new ticket for this
issue
for RHEL5.6alpha too.

- The sosreport file is attached.
sosreport-rhel60GA-Intel64-20101101093400-e832.tar.xz
(The md5sum is: cb2aaf4acbd4d683e22eca73e9b7e832)

Comment 1 Alan Matsuoka 2010-12-09 15:21:56 UTC
Created attachment 467768 [details]
sosreport-rhel60GA-Intel64-20101101093400-e832.tar.xz

Comment 7 Andreas Schwab 2011-01-10 14:15:59 UTC
Please provide a test case.

Comment 8 Max Matveev 2011-01-11 03:35:28 UTC
The test case is in the original submission - compile the small program
in 'reproducer', run it with strace -f, see it hang.

Comment 9 Andreas Schwab 2011-01-11 08:44:23 UTC
There is not a single use of clone in the test case.

Comment 10 Max Matveev 2011-01-12 02:04:29 UTC
Created attachment 472934 [details]
test which uses clone

Comment 18 Florian Nadge 2011-01-27 15:10:31 UTC
Please be so kind and add a few key words to the Technical Note field of this
Bugzilla entry using the following structure:

Cause:

Consequence:

Fix:

Result:


For details, see:
https://bugzilla.redhat.com/page.cgi?id=fields.html#cf_release_notes

Thanks

Comment 19 Florian Nadge 2011-01-27 15:10:31 UTC
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Cause:

Consequence:

Fix:

Result:

Comment 20 Andreas Schwab 2011-01-28 12:54:03 UTC
    Technical note updated. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    Diffed Contents:
@@ -1,7 +1,10 @@
 Cause:
+When strace is used, waitpid without __WCLONE or __WALL option waits for children created by clone
 
 Consequence:
 
 Fix:
+don't suspend process calling waitpid
 
-Result:+Result:
+don't suspend process calling waitpid

Comment 21 Max Matveev 2011-01-30 22:59:29 UTC
May I suggest we use the text from the following Knowledgebase article for
technotes?
 
https://access.redhat.com/kb/docs/DOC-45317

Comment 38 errata-xmlrpc 2011-03-10 07:45:25 UTC
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2011-0338.html