# Crash when initializing app built and run from Ubuntu 20.04

**URL:** <https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265>\
**Category:** Development\
**Tags:** build\
**Created:** [August 31, 2020, 7:56pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265 "2020-08-31T19:56:57Z")\
**Posts on this page:** 10\
**Page:** 2

<div class="post-metadata">

**Author:** ![Amir\_Zolal](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amir_zolal/32/9423_2.png) [@Amir\_Zolal](https://discourse.slicer.org/u/Amir_Zolal)\
**Post date:** [January 14, 2021, 8:31am UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/21 "2021-01-14T08:31:38Z")

</div>

Hello,

so I still have this problem:

qt5ct: using qt5ct plugin  
error: [/home/zolal/Slicer/Slicer-build/bin/./SlicerApp-real] exit abnormally - Report the problem.

Now, when I try the following:

QT\_DEBUG\_PLUGINS=1 ./Slicer

Slicer runs!

Now, I have tried various other solutions proposed here in the forum, inclusive disabling Python SSL, but that was not so successful.  
So I guess the problem is with QT, any idea how to get nearer to the issue?

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [January 14, 2021, 2:56pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/22 "2021-01-14T14:56:06Z")

</div>

Can you get a stack trace?  
Maybe it is the same issue as this: [qt5ct / Tickets / #77 Krita crashes with qt5ct plugin with Qt5.15](https://sourceforge.net/p/qt5ct/tickets/77/)

---

<div class="post-metadata">

**Author:** ![Amir\_Zolal](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amir_zolal/32/9423_2.png) [@Amir\_Zolal](https://discourse.slicer.org/u/Amir_Zolal)\
**Post date:** [January 14, 2021, 5:22pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/23 "2021-01-14T17:22:28Z")

</div>

strace\>  
[https://pastebin.ubuntu.com/p/mqsy8Ytn94/](https://pastebin.ubuntu.com/p/mqsy8Ytn94/)

---

<div class="post-metadata">

**Author:** ![Amir\_Zolal](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amir_zolal/32/9423_2.png) [@Amir\_Zolal](https://discourse.slicer.org/u/Amir_Zolal)\
**Post date:** [January 14, 2021, 6:08pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/24 "2021-01-14T18:08:32Z")

</div>

Somehow I do not understand what all the EAGAIN resource not available means. Is this the problem?

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [January 14, 2021, 7:03pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/25 "2021-01-14T19:03:42Z")

</div>

This file seems to be list of system calls. It is somewhat interesting, but the stack trace could be more informative. Could you print that, too?

---

<div class="post-metadata">

**Author:** ![Amir\_Zolal](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amir_zolal/32/9423_2.png) [@Amir\_Zolal](https://discourse.slicer.org/u/Amir_Zolal)\
**Post date:** [January 14, 2021, 9:06pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/26 "2021-01-14T21:06:54Z")

</div>

So, one would think that strace will produce the stacktrace and not a trace of system calls, right? 🙂

Now. I tried with gdb, maybe this will help someone:

gdb ./Slicer 2\>&1 | tee ~/gdb-Slicer.txt  
(gdb) handle SIG33 pass nostop noprint  
Signal Stop Print Pass to program Description  
SIG33 No No Yes Real-time event 33  
(gdb) set pagination 0  
(gdb) set follow-fork-mode child  
(gdb) run  
Starting program: /home/zolal/Slicer/Slicer-build/Slicer  
[Thread debugging using libthread\_db enabled]  
Using host libthread\_db library “/lib/x86\_64-linux-gnu/libthread\_db.so.1”.  
[New Thread 0x7ffff6e35700 (LWP 96055)]  
[Attaching after Thread 0x7ffff7622140 (LWP 96054) fork to child process 96056]  
[New inferior 2 (process 96056)]  
[Detaching after fork from parent process 96054]  
[Inferior 1 (process 96054) detached]  
[Thread debugging using libthread\_db enabled]  
Using host libthread\_db library “/lib/x86\_64-linux-gnu/libthread\_db.so.1”.  
process 96056 is executing new program: /home/zolal/Slicer/Slicer-build/bin/SlicerApp-real  
[Thread debugging using libthread\_db enabled]  
Using host libthread\_db library “/lib/x86\_64-linux-gnu/libthread\_db.so.1”.  
[New Thread 0x7fffd5473700 (LWP 96059)]  
qt5ct: using qt5ct plugin  
[New Thread 0x7fffcffff700 (LWP 96060)]  
[New Thread 0x7fffce9bb700 (LWP 96062)]  
[New Thread 0x7fffce1ba700 (LWP 96063)]  
[New Thread 0x7fffcd9b9700 (LWP 96064)]  
[New Thread 0x7fffcd1b8700 (LWP 96065)]  
[New Thread 0x7fffcc9b7700 (LWP 96066)]  
[New Thread 0x7fffb7fff700 (LWP 96067)]  
[New Thread 0x7fffb3abe700 (LWP 96085)]  
[New Thread 0x7fffb2e8d700 (LWP 96086)]  
[New Thread 0x7fffb1aff700 (LWP 96087)]  
[New Thread 0x7fffb12fe700 (LWP 96088)]

Thread 2.1 “SlicerApp-real” received signal SIGSEGV, Segmentation fault.  
[Switching to Thread 0x7fffd6406d40 (LWP 96056)]  
0x00007fffe6275d71 in ?? () from /lib/x86\_64-linux-gnu/libQt5Widgets.so.5

another funny thing:

running sudo ./Slicer works!!

qmake --version  
QMake version 3.1  
Using Qt version 5.12.8 in /usr/lib/x86\_64-linux-gnu

Somehow I am getting the feeling that this might be related to the fact that my laptop was upgraded from 16.04 -\> 18.04 -\> 20.04 like in the case of the other user and maybe there is a bug in updating Qt.

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [January 14, 2021, 9:08pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/27 "2021-01-14T21:08:43Z")

</div>

Yes, if sudo works then it suggests that the root cause may be some incorrectly permissions.

---

<div class="post-metadata">

**Author:** ![Amir\_Zolal](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amir_zolal/32/9423_2.png) [@Amir\_Zolal](https://discourse.slicer.org/u/Amir_Zolal)\
**Post date:** [January 16, 2021, 6:57am UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/28 "2021-01-16T06:57:26Z")

</div>

For future reference: the build using the default Qt version did not work (Qt version 5.12.8 in /usr/lib/x86\_64-linux-gnu).

After installing Qt from Qt website using the online installer (with all modules! not the default option, because in default you will miss QtScript etc.) use cmake like this:

cmake -DCMAKE\_BUILD\_TYPE:STRING=Release -DQt5\_DIR=/opt/Qt/5.15.2/gcc\_64/lib/cmake/Qt5 …/SlicerSource/

Then make, naturally.  
Slicer runs without problems now.

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [January 16, 2021, 3:43pm UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/29 "2021-01-16T15:43:42Z")

</div>

Thanks for the update. Do you think we should include a note about this in the Slicer build instructions or yours was a very special case?

---

<div class="post-metadata">

**Author:** ![Amir\_Zolal](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amir_zolal/32/9423_2.png) [@Amir\_Zolal](https://discourse.slicer.org/u/Amir_Zolal)\
**Post date:** [January 17, 2021, 8:40am UTC](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265/30 "2021-01-17T08:40:17Z")

</div>

Hi, I think that before you get more similar reports, this was a special case.

[Previous page](https://discourse.slicer.org/t/crash-when-initializing-app-built-and-run-from-ubuntu-20-04/13265.md?page=1)