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Bug #425

closed

lttng-sessiond gets a segmentation fault

Added by Mathieu Bain almost 12 years ago. Updated almost 12 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
Target version:
Start date:
01/18/2013
Due date:
% Done:

0%

Estimated time:

Description

Situation:
A session is running and just before destroying the session, we launch a bunch of instrumented application.
This made lttng-sessiond do a core dump.

By analyzing the core file, the core dump happened in create_ust_channel.c at line 783
I attached the small analyze that I ran with gdb on the core file.

The version of Lttng used is 1.2.0 with:
lttng-tools: 2.1.1
lttng-ust: 2.1.0
userspace-rcu: 0.7.5


Files

logs.txt (16.6 KB) logs.txt Mathieu Bain, 01/18/2013 04:07 PM
Actions #1

Updated by David Goulet almost 12 years ago

  • Status changed from New to Confirmed
  • Assignee set to David Goulet
  • Target version set to 2.1 stable
Actions #2

Updated by David Goulet almost 12 years ago

If you can reproduce that with no optimization (gcc -O0), it would be great since the ret value here is quite important. It seems that a ustctl_create_channel call returned a positive value but actually failed to populate the obj.

Furthermore, no optimization will ensure that the segfault is really at that place with more information as well.

Thanks!

Actions #3

Updated by David Goulet almost 12 years ago

This might be fixed with the latest commit of lttng-ust.

(stable-2.1) c7b9470b6849bc42d0c3a835b917e764e8c13fc9

There was a code path that could have sent a positive value on error.

Thanks

Actions #4

Updated by David Goulet almost 12 years ago

  • Status changed from Confirmed to Feedback
Actions #5

Updated by Mathieu Bain almost 12 years ago

Hi David,

I tested the patch and up to now i don't see the issue any more.
If this shows up sometime later, i will raise a new bug

Thanks

Actions #6

Updated by David Goulet almost 12 years ago

  • Status changed from Feedback to Resolved

Ok. Fair enough, I'll close this one since we can't do much for now.

Thanks!

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