Bug 451859 - ptrace ATTACH, then CONT with signal fails
ptrace ATTACH, then CONT with signal fails
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
All Linux
low Severity medium
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Assigned To: Kernel Maintainer List
Fedora Extras Quality Assurance
Depends On:
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Reported: 2008-06-17 15:54 EDT by Tom Fleck
Modified: 2009-07-14 14:05 EDT (History)
1 user (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2009-07-14 14:05:57 EDT
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Description Tom Fleck 2008-06-17 15:54:38 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/20080404 Firefox/

Description of problem:
ptrace behavior apparently changed big-time between FC3=RHEL4=2.6.9 and FC6=2.6.18, such that continuing the debugged process with a signal after attaching no longer works.

Attached is my test program. It's long and verbose, I'm sorry, but I wanted to be clear. As comments say, there are 2 ways to build it that manifest the bug in different ways.


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

How reproducible:

Steps to Reproduce:
1. Compile test program:
gcc ptracebug.c -o ptrace_from_parent
2. Run test program:

Actual Results:
--- Show that ptrace(CONT, blocked-signal) fails on FC6
 If test dones't print PASSED, it failed.
APP=3440: wait for SIGUSR1 from DEB=3439
DEB=3439 sleeping for a second
DEB=3439: ptrace attach to APP=3440
DEB=3439: CONT APP=3440 with signal 10
DEB=3439 looks ok
PID=3439: DEB OK

Expected Results:
 If test dones't print PASSED, it failed.
APP=13766: wait for SIGUSR1 from DEB=13765
DEB=13765 sleeping for a second
DEB=13765: ptrace attach to APP=13766
DEB=13765: CONT APP=13766 with signal 10
DEB=13765 looks ok
PID=13765: DEB OK

APP=13766 sleeping for a second
ripley:tjf 265>> APP=13766 looks ok

Additional info:
See also https://bugzilla.redhat.com/show_bug.cgi?id=451849
Comment 1 petrosyan 2008-06-17 17:38:23 EDT
Fedora Core 6 and Fedora 7 are no longer maintained.
Can you reproduce this bug in Fedora 8 or Fedora 9?
Comment 2 Jakub Jelinek 2008-06-17 22:18:09 EDT
This has nothing to do with glibc.  ptrace is a syscall.
Comment 3 petrosyan 2008-06-27 13:10:21 EDT
Tom, can you reproduce this bug in Fedora 8 or Fedora 9?
Comment 4 Tom Fleck 2008-06-27 13:14:05 EDT
Sorry, I don't have those available yet.  I've got a vmware machine with FC9 on
it now but no gcc yet.  I'll comment when I've done that.  
Comment 5 Tom Fleck 2008-06-27 13:50:11 EDT
The bug reproduces on FC9 using test-case binary built on rhel4 with gcc 3.4.6,
and a binary built on rhel5 with gcc 4.1.2.  Is that good enough? 
Comment 6 petrosyan 2008-06-27 14:57:56 EDT
I could reproduce your bug by compiling and running your test-binaries on Fedora
9 using gcc-4.3.0 on a x86_64 architecture.
Comment 7 Bug Zapper 2009-06-09 21:40:26 EDT
This message is a reminder that Fedora 9 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
and issuing updates for Fedora 9.  It is Fedora's policy to close all
bug reports from releases that are no longer maintained.  At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
'version' of '9'.

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Comment 8 Bug Zapper 2009-07-14 14:05:57 EDT
Fedora 9 changed to end-of-life (EOL) status on 2009-07-10. Fedora 9 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of 
Fedora please feel free to reopen this bug against that version.

Thank you for reporting this bug and we are sorry it could not be fixed.

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