Bug 230423 - ptrace causing SIGSEGV in debugged process when sending SIGKILL to it.
Summary: ptrace causing SIGSEGV in debugged process when sending SIGKILL to it.
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 6
Hardware: i386
OS: Linux
Target Milestone: ---
Assignee: Roland McGrath
QA Contact: Brian Brock
Depends On:
TreeView+ depends on / blocked
Reported: 2007-02-28 19:37 UTC by Kevin Van Brunt
Modified: 2007-11-30 22:11 UTC (History)
3 users (show)

Fixed In Version: 2.6.20-1.2925.fc6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2007-03-20 17:27:07 UTC
Type: ---

Attachments (Terms of Use)
A test c program that demonstrates the bug. (1.02 KB, text/plain)
2007-02-28 19:41 UTC, Kevin Van Brunt
no flags Details

Description Kevin Van Brunt 2007-02-28 19:37:56 UTC
From Bugzilla Helper:
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30)

Description of problem:
I have written a small program to demonstrate this bug.  It causes ptrace to trace /bin/ls.  After the first waitpid, the parent sends a SIGKILL to ls and ls performs a segmentation fault.  /bin/ls is only used as an example.  Any traced process has the same problem.  I have traced xterm, firefox, and gnome-cd as well and seen the bug.

The code will be attached to this bug report.

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

How reproducible:

Steps to Reproduce:
1. Compile and run the attached code.

Actual Results:
The message "GOT SIGSEGV" should appear because the traced program performs a segmentation fault.

Expected Results:
The traced program should not perform a segmentation fault and no message should appear.

Additional info:

Comment 1 Kevin Van Brunt 2007-02-28 19:41:19 UTC
Created attachment 148952 [details]
A test c program that demonstrates the bug.

Comment 2 Albert Cahalan 2007-03-07 04:31:25 UTC
A pure kernel does not show the problem at all. I even tried adding
sched_yield in various places to see if scheduling order would affect things.

This is probably a utrace bug.

Comment 3 Roland McGrath 2007-03-19 23:03:55 UTC
I reproduced this on 2.6.19-1.2911.fc6 but not on 2.6.20-1.2925.fc6.
Please try the latest fc6 update kernel and verify that the problem is gone for you.

Comment 4 Kevin Van Brunt 2007-03-20 17:20:41 UTC
It looks to be fixed in 2.6.20-1.2925.fc6.

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