Bug 387247 - okular [12.17beta] crash upon highlighting text in pdfs
Summary: okular [12.17beta] crash upon highlighting text in pdfs
Status: RESOLVED FIXED
Alias: None
Product: okular
Classification: Applications
Component: PDF backend (show other bugs)
Version: unspecified
Platform: openSUSE Linux
: NOR major
Target Milestone: ---
Assignee: Okular developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-11-24 07:27 UTC by Robby Engelmann
Modified: 2018-04-06 05:46 UTC (History)
5 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
okular backtrace 1 (9.16 KB, text/plain)
2017-11-29 10:29 UTC, Robby Engelmann
Details
screenshot (559.76 KB, image/png)
2017-11-29 10:31 UTC, Robby Engelmann
Details
other example (722.43 KB, application/pdf)
2017-12-04 14:55 UTC, Robby Engelmann
Details

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Description Robby Engelmann 2017-11-24 07:27:28 UTC
Highlighting 5-10 textpositions in a  pdf leads to crash every time. Unfortunately, drkonqi is not triggered here, thus I do not have a backtrace.
It is not limited to long pdfs as first thought (https://bugs.kde.org/show_bug.cgi?id=375506)
Comment 1 null 2017-11-24 22:22:48 UTC
Thanks for reporting, but I cannot reproduce with a self-compiled Okular 17.12 Beta on Tumbleweed (you mentioned in the other bug that you were using Tumbleweed, too) as well as the Beta one from KDE:/Applications/KDE_Frameworks5_openSUSE_Tumbleweed.

Please attach a PDF which is crashing for you and a provide a screenshot (or screen recording) of the highlights right before the crash.

Do you get any additional output when starting Okular from a console?

To manually create a backtrace, refer to https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports#Retrieving_a_backtrace_with_GDB
Comment 2 Robby Engelmann 2017-11-28 11:58:08 UTC
console output:
okular Flow_Guideline.pdf 
QFSFileEngine::open: No file name specified
Illegal icon group:  7
kf5.kio.core: Invalid URL: QUrl("Flow_Guideline.pdf")
kf5.kio.core: Invalid URL: QUrl("Flow_Guideline.pdf")
Segmentation fault (core dumped)
Comment 3 Robby Engelmann 2017-11-28 12:00:37 UTC
The pdf I currently use is found here (too large to upload as attachment): http://onlinelibrary.wiley.com/doi/10.1002/eji.201646632/pdf
Comment 4 null 2017-11-28 22:29:33 UTC
Thanks for the additional info. Console output looks normal, except for the last line ;)

However, I still could not reproduce the crash. More ideas to try:
- What does "Highlighting 5-10 textpositions" mean exactly? Try uploading a screenshot right before the crash.
- Provide a backtrace, so we can see in which direction to investigate further.
- Do you have any additional repositories enabled? This sometimes leads to weird side effects for libraries like Poppler (Okular's PDF rendering backend).
- Is you system fully up-to-date with "zypper dup"?
- Perhaps this is a graphics driver issue? Which driver do you use? Do you have another system with different hardware to test on?
- Try "repairing" the PDF with "qpdf in.pdf out.pdf" and see if it still crashes.
Comment 5 Robby Engelmann 2017-11-29 10:29:26 UTC
Created attachment 109111 [details]
okular backtrace 1
Comment 6 Robby Engelmann 2017-11-29 10:30:38 UTC
-bt and screenshot attached
-system is fully upgraded
-modesetting with an intel skylake is in use

I hope that helps
Comment 7 Robby Engelmann 2017-11-29 10:31:02 UTC
Created attachment 109112 [details]
screenshot
Comment 8 null 2017-11-30 00:54:56 UTC
Sorry to say, still cannot reproduce the crash (and I tried _very_ hard).

Looking at the backtrace and your hardware, I got another idea. Please run the following two commands and provide the output (the second one might need "zypper in xdpyinfo"):
- grep DPI /var/log/Xorg.0.log
- xdpyinfo | grep -B2 resolution

Also: Can you confirm highlighting the same way in another PDF does not lead to a crash?

And just to be sure: You do not have a touchscreen by any chance, do you?

(BTW, seeing you removed the menubar: To get even more vertical space, Okular allows to remove the bottom bar too and add it back again as a "button" in the toolbar.)
Comment 9 Robby Engelmann 2017-11-30 13:13:51 UTC
Here the outputs:

- grep DPI /var/log/Xorg.0.log:
[   188.617] (==) modeset(0): DPI set to (96, 96)
[   188.965] (II) event7  - (II) Logitech MX Master: (II) device set to 1000 DPI
[   188.980] (II) event7  - (II) Logitech MX Master: (II) device set to 1000 DPI
[  2212.944] (II) event7  - (II) Logitech MX Master: (II) device set to 1000 DPI
[  2212.984] (II) event7  - (II) Logitech MX Master: (II) device set to 1000 DPI


- xdpyinfo | grep -B2 resolution
screen #0:
  dimensions:    1920x1080 pixels (508x285 millimeters)
  resolution:    96x96 dots per inch


Highlighting the same way lead to a crash in at least one other pdf too. I do not have a touchscreen (using a tuxedo infinity book 13 v2).
Comment 10 null 2017-11-30 23:25:41 UTC
Hmm, looks normal, too. Not sure what to do now.

After playing around some more, I could finally observe a crash. Unfortunately, I'm not able to crash Okular a second time to capture anything…

Albert: Do you see any hints in the backtrace?

When setting a breakpoint on Page::width, pressing the mouse button and moving a single pixel to select (no matter whether annotation or regular text selection), I get the same backtrace, without the crash of course. I looks quite normal, but why would it crash afterwards?
Comment 11 Albert Astals Cid 2017-12-03 19:04:11 UTC
(In reply to Robby Engelmann from comment #3)
> The pdf I currently use is found here (too large to upload as attachment):
> http://onlinelibrary.wiley.com/doi/10.1002/eji.201646632/pdf

Please send us one with all your existing annotations and also describe clearly which annotation you add and in which page.
Comment 12 Robby Engelmann 2017-12-04 14:55:48 UTC
Created attachment 109208 [details]
other example
Comment 13 Robby Engelmann 2017-12-04 14:57:35 UTC
I attached a pdf as an example. However, it does not matter which pdf is used. If I use the text highlighting annotation, okular will crash after adding 3-8 further highlights to a previously saved pdf containing text highlighting annotations.
Comment 14 Robby Engelmann 2017-12-04 14:59:32 UTC
Not to forget: It is also the same for the 1.2.90 version of okular (RC of KDE apps 17.12).
Comment 15 Albert Astals Cid 2017-12-04 16:06:12 UTC
(In reply to Robby Engelmann from comment #14)
> Not to forget: It is also the same for the 1.2.90 version of okular (RC of
> KDE apps 17.12).

So you get the crash both on 1.2.90 and say 1.2.3?
Comment 16 Albert Astals Cid 2017-12-04 16:10:40 UTC
(In reply to Robby Engelmann from comment #13)
> I attached a pdf as an example. However, it does not matter which pdf is
> used. If I use the text highlighting annotation, okular will crash after
> adding 3-8 further highlights to a previously saved pdf containing text
> highlighting annotations.

Still can't reproduce, could you run
  valgrind okular myfile.pdf
on a terminal (it will be slower) and do what you usually do to make it crash and then paste here the output of the valgrind command on the command line?
Comment 17 null 2017-12-05 20:16:20 UTC
For both documents, I can now reproduce the crash pretty reliably:
- Add highlighting annotation.
- Save document. (← This is an essential prerequisite.)
- Scroll to a new page to trigger rendering (← Somehow this is needed to get in a bad state, but only for the first document.)
- Keep adding more highlighting annotations and scrolling further until the crash triggers (it won't always crash for the first one).

(IOW, it's important to be as detailed as possible when reporting a bug and when requesting information from a bug reporter, otherwise it's just plain guessing…)

In fact, even with autotests/data/file1.pdf a crash is now trivial to trigger (highlight → save → highlight). I bisected back and forth in both Okular and Poppler, and ultimately Okular's ca5422d0e9ad ("Implement swapBackingFile for the PDF backend") is the culprit (tested with Poppler master). The only explanation I have is that the new annotation saving feature was mainly tested with the pen tool, but less so with the highlighter, which was not wise reading that commit message now.

Albert: Backtrace is the same as above, let me know if you still cannot reproduce and need the Valgrind log. Removing "qDeleteAll( pagePrivatesToDelete )" fixes the crash for me, because then accessing "d" in "Page::width" won't segfault anymore. However, now "d" leaks obviously. Any tips on how the oldPage/newPage pointer swapping is supposed to work and the leak could be prevented?

Otherwise, I'd say leaking a little bit is better than crashing, given that the final release is tomorrow…
Comment 18 Robby Engelmann 2017-12-05 20:24:28 UTC
Oki, I learn to be as precise as possible the next time. I did not expect, that saving is the important point here, although I am well aware that I saved always before the bug got triggered.
Comment 19 Albert Astals Cid 2017-12-05 22:08:33 UTC
Git commit 4e6c9f8f7ab5369528802a5012865523afb4747b by Albert Astals Cid.
Committed on 05/12/2017 at 22:07.
Pushed by aacid into branch 'Applications/17.12'.

Fix crash when accessing text page after save

text page was storing a pointer to a PagePrivate pointer but those die
after saving so we need to store a Page pointer since those are stable.

M  +2    -2    core/page.cpp
M  +12   -10   core/textpage.cpp
M  +1    -1    core/textpage_p.h

https://commits.kde.org/okular/4e6c9f8f7ab5369528802a5012865523afb4747b
Comment 20 null 2017-12-05 23:01:19 UTC
Robby: Thanks again for testing the Beta and RC releases. You were the only one reporting this serious bug with the new annotation saving feature, even though it will affect almost everybody using highlighting. Keep beta testing, so we have a chance to fix mistakes in time ;)

Albert: Thanks for the fix.