Segfaults

Christian Ehrhardt christian.ehrhardt at canonical.com
Thu Jun 23 06:08:09 UTC 2016


Hi Tyler,
well in that case we have to find why your apport isn't collecting the
crash, because that is the start to look deeper into it.
There is /var/log/apport* which might help you to understand what is going
on.

I quickly ran this:
#include <signal.h>
int main()
{
    raise(SIGSEGV);
}

And got:
cat /var/log/apport.log
ERROR: apport (pid 26269) Thu Jun 23 07:50:47 2016: called for pid 26268,
signal 11, core limit 0
ERROR: apport (pid 26269) Thu Jun 23 07:50:47 2016: executable:
/tmp/segfaultme (command line "./segfaultme")
ERROR: apport (pid 26269) Thu Jun 23 07:50:47 2016: executable does not
belong to a package, ignoring

Well that is fair, but at least it picked up the fault happening for sure.

Next I let something segfault that is in a package
md5sum /dev/urandom &
kill --signal SIGSEGV $!

Here I already got my "there was a crash popup by apport" since I'm on a
desktop.
In the log I found:
ERROR: apport (pid 28384) Thu Jun 23 08:01:01 2016: called for pid 28159,
signal 11, core limit 0
ERROR: apport (pid 28384) Thu Jun 23 08:01:01 2016: executable:
/usr/bin/md5sum (command line "md5sum /dev/urandom")
ERROR: apport (pid 28384) Thu Jun 23 08:01:01 2016: gdbus call error:
Error: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name
org.gnome.SessionManager was not provided by any .service files
ERROR: apport (pid 28384) Thu Jun 23 08:01:01 2016: debug: session gdbus
call:
ERROR: apport (pid 28384) Thu Jun 23 08:01:02 2016: wrote report
/var/crash/_usr_bin_md5sum.1000.crash


Debugging starts like:
sudo apport-retrace --stdout --rebuild-package-info
 /var/crash/_usr_bin_md5sum.1000.crash
sudo apport-retrace --rebuild-package-info --gdb
/var/crash/_usr_bin_md5sum.1000.crash

I hope that helps to find why crashes aren't collected for you and then
also about the first few steps into debugging if you like.


Christian Ehrhardt
Software Engineer, Ubuntu Server
Canonical Ltd

On Wed, Jun 22, 2016 at 9:45 PM, Tyler Petersen <tpetersen at xes-inc.com>
wrote:

> Hi everyone,
>
> I am still having problems with this. I made sure apport was running and
> the /var/crash directory exists. But when
> a segfault happens nothing is written to the directory. The segfaults also
> seem to come and go.
>
> Thanks,
>
> Tyler
>
> ------------------------------
> *From: *"Christian Ehrhardt" <christian.ehrhardt at canonical.com>
> *To: *"Tyler Petersen" <tpetersen at xes-inc.com>
> *Cc: *"ubuntu-server" <ubuntu-server at lists.ubuntu.com>
> *Sent: *Wednesday, June 15, 2016 10:47:37 AM
> *Subject: *Re: Segfaults
>
> Hi Tyler,
> when an appliaction is crashing it should leave a .crash file in
> /var/crash which stores debugging information.
> Base on that you can automatically report a bug that has most of the info
> to start with.
> See https://help.ubuntu.com/community/ReportingBugs#Crash_reports for
> more.
>
> If you want to look into it more yourself I'd recommend starting with
> https://wiki.ubuntu.com/DebuggingProgramCrash
> https://www.piware.de/2011/08/apport-retrace-made-useful/
>
> Kind regards,
> Christian
>
> Christian Ehrhardt
> Software Engineer, Ubuntu Server
> Canonical Ltd
>
> On Wed, Jun 15, 2016 at 3:55 PM, Tyler Petersen <tpetersen at xes-inc.com>
> wrote:
>
>> Hi everyone,
>> We are currently experiencing some odd issues on our ubuntu servers
>> (14.04). We
>> keep seeing segfault messages for mdadm but we are not sure if they are a
>> bug or
>> a real problem. The servers are two completely different physical boxes.
>> Both
>> are running the 3.13.0-88-generic kernal and mdadm version
>> 3.2.5-5ubuntu4.3.
>> Here are the two most common errors we see: "[2201076.898901]
>> mdadm[17298]:
>> segfault at 8 ip 00007f3445891d16 sp 00007ffc2cd425f8 error 4 in
>> libc-2.23.so[7f3445807000+1c0000]" and "[39304.894195] mdadm[17613]:
>> segfault at
>> 0 ip 00007fb29477cd16 sp 00007ffe8ce211d8 error 4 in
>> libc-2.23.so[7fb2946f2000+1c0000]". Any help or advice would be greatly
>> apperciated.
>> Thanks,
>> Tyler
>>
>> --
>> ubuntu-server mailing list
>> ubuntu-server at lists.ubuntu.com
>> https://lists.ubuntu.com/mailman/listinfo/ubuntu-server
>> More info: https://wiki.ubuntu.com/ServerTeam
>>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-server/attachments/20160623/f91cf190/attachment.html>


More information about the ubuntu-server mailing list