Bug 232369 - Exit notifications missing when tracing multi-threaded processes
Exit notifications missing when tracing multi-threaded processes
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Roland McGrath
Martin Jenner
: Regression
Depends On: 232236
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Reported: 2007-03-14 21:03 EDT by Roland McGrath
Modified: 2007-11-30 17:07 EST (History)
2 users (show)

See Also:
Fixed In Version: RHBA-2007-0959
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2007-11-07 14:44:17 EST
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Regression: ---
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Verified Versions:
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RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

  None (edit)
Description Roland McGrath 2007-03-14 21:03:45 EDT
+++ This bug was initially created as a clone of Bug #232236 +++

Description of problem:
When tracing multiple threads in a process using ptrace the Fedora Core kernel
only delivers an exit notification through wait for the initial thread. Vanilla
Linux kernels deliver an exit notification for each traced thread.

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

How reproducible:
Every time.

Steps to Reproduce:
1. Untar the attached test.
2. cd exit-test
3. make
4. ./monitor

Actual results:
Prints only one exit notification.

Expected results:
Should print two exit notifications.

Additional info:

For a less synthetic testcase, strace is also affected by this. Try compiling
this program with "gcc -fopenmp -o foo foo.c":

int main(int argc, char **argv) {
    int i;
#pragma omp parallel for
    for (i = 0; i < 1; i++)

    return 0;

Then trace it with "strace -f ./foo". Strace reports multiple detaches for the
same thread or bogus SIGSEGVs:

[pid  4586] futex(0x886b048, FUTEX_WAKE, 1) = 1
[pid  4585] <... futex resumed> )       = 0
[pid  4585] futex(0x886b048, FUTEX_WAKE, 1) = 0
[pid  4585] exit_group(0)               = ?
Process 4585 detached
Process 4586 detached
Process 4585 detached

[pid  4589] futex(0x19d830, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid  4588] <... futex resumed> )       = 0
[pid  4588] exit_group(0)               = ?
[pid  4589] <... futex resumed> )       = 9
[pid  4589] --- SIGSEGV (Segmentation fault) @ 0 (0) ---

-- Additional comment from magnus_vesterlund@hotmail.com on 2007-03-14 11:08 EST --
Created an attachment (id=150042)
Test case

-- Additional comment from cebbert@redhat.com on 2007-03-14 11:13 EST --
Please test 2.6.20-1.2925.fc6

It's in Fedora testing now and should be released today.

-- Additional comment from roland@redhat.com on 2007-03-14 14:53 EST --
Looks like this is still a problem.

-- Additional comment from roland@redhat.com on 2007-03-14 20:14 EST --
Created an attachment (id=150103)
test case contained in one source file

This is the version of the test case I'm using.

-- Additional comment from roland@redhat.com on 2007-03-14 20:56 EST --
Created an attachment (id=150106)
fix patch

I've fixed the bug and the attached patch is now part of the "upstream" utrace

-- Additional comment from roland@redhat.com on 2007-03-14 21:01 EST --
I've committed the new utrace patch to the rawhide kernel cvs.
The attached patch can be folded into the utrace patch for fc6.
Comment 1 Roland McGrath 2007-03-14 21:07:25 EDT
See attachments to bug #232236 for test case and fix patch.
This is a regression vs RHEL4 and all prior and upstream kernels.
The fix will be included with other utrace updates in a replacement utrace patch
for 5.1.
Comment 2 RHEL Product and Program Management 2007-03-14 22:04:16 EDT
This bugzilla has Keywords: Regression.  

Since no regressions are allowed between releases, 
it is also being proposed as a blocker for this release.  

Please resolve ASAP.
Comment 5 RHEL Product and Program Management 2007-06-20 08:31:41 EDT
This request was evaluated by Red Hat Kernel Team for inclusion in a Red
Hat Enterprise Linux maintenance release, and has moved to bugzilla 
status POST.
Comment 6 Don Zickus 2007-07-19 16:05:34 EDT
in kernel-2.6.18-30.el5
Comment 8 Mike Gahagan 2007-09-11 14:52:29 EDT
confirmed fix using testcase attached as attachment (id=150103) 
Comment 10 errata-xmlrpc 2007-11-07 14:44:17 EST
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 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.


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