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Bug 80264

Summary: strace -f breaks WNOHANG
Product: Red Hat Enterprise Linux 2.1 Reporter: Mike Gahagan <mgahagan>
Component: straceAssignee: Roland McGrath <roland>
Status: CLOSED ERRATA QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 2.1CC: tao
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2003-01-10 23:07:04 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Description Flags
tarball of strace output and ksh test script.
strace-4.4.cvs20021221rh-1 on 8.0
tarball showing failure with strace-4.4.cvs20021221rh-1 none

Description Mike Gahagan 2002-12-23 16:29:05 UTC
Description of problem:

Strace -f will break with programs that use the wait4 system call (aka waitpid
or wait3) with the WNOHANG flag when they have live children.

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

strace-4.3-2 (comes with AS 2.1)
(problem exists w/ 7.x and 8.0)

How reproducible:

Always. AT&T's ksh is a reliable reproducer.

Steps to Reproduce:
1.Install AT&T ksh and any version of strace from above.
2.Run attached test script.
Actual results:

See attached

Expected results:

strace should be able to follow processes.

Additional info:

Comment 1 Mike Gahagan 2002-12-23 16:32:10 UTC
AT&T's ksh93 is available from

Comment 2 Mike Gahagan 2002-12-23 16:33:16 UTC
Created attachment 88867 [details]
tarball of strace output and ksh test script.

Comment 3 Mike Gahagan 2002-12-23 18:07:42 UTC
Created attachment 88868 [details]
strace-4.4.cvs20021221rh-1 on 8.0

same failure as before

Comment 4 Mike Gahagan 2002-12-23 18:09:35 UTC
Created attachment 88869 [details]
tarball showing failure with strace-4.4.cvs20021221rh-1

Comment 5 Roland McGrath 2002-12-27 01:40:03 UTC
I am confused.  There is no sign of the bug in the attachments here.
The failure mode before was that strace interfered with the normal functioning
of ksh, indicated by the "Warning: error(s) creating ..." message produced from
the script.  Those messages do not appear in your transcripts attached here.
Please state explicitly for the record what criteria you are applying when
you say that there is still a bug here.  

Comment 6 Roland McGrath 2003-01-10 23:07:04 UTC
Version 4.4.91-1 should work fine.

Comment 7 John Flanagan 2003-12-19 17:57:54 UTC
An errata 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 the 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.