apport information
** Tags added: apport-collected
** Description changed:
# DESCRIPTION :
Playing a "partially corrupt" video starts normally, then starts showing
visual artifacts (apparition of a red gradient on the bottom of the viewframe
and a green gradient on top), which increase in intensity over time (can result
in brigth blinking, black bars appearing in the middle of the video, etc.) and
can, at some point, result in a complete system freeze.
Once the system is frozen, the mouse can still move, but nothing else on
the screen reacts - neither on click nor on hover. After a few seconds,
the screens (I have two screens) go black briefly, then re-appear to
show complete noise, with a 64x64-pixel-box of lighter noise around
where the mouse is. The mouse can still move normally (the lighter 64x64
box moves at the same speed my mouse moved before the crash - no lag, no
FPS drop).
# IMPORTANT BEHAVIORAL OBSERVATIONS :
- Alt + SysReq + R, E, I, S, U, B DOES NOT RESPOND (that's why I believe the
kernel is affected). I tried several times, waiting a full second between each
input; no response. I believe I was doing it correctly because I have used that
technique successfully several times in the past on different systems.
- The bug first occurred a few months ago, and since then I have updated my
system several times (using Ubuntu's built-in graphical update notifier - I've
installed everything update I saw), and none of the updates have fixed the
problem. I did notice, though, that lately the bug was harder to reproduce, but
I have no idea if that correlation means causation or not.
- The same physical machine runs another instance of the exact same operating
system (Ubuntu 18.04.4 LTS) on a different hard drive. I just switch hard
drives manually to change systems. The other system has always used VLC to play
videos as Totem lacks codecs to play the videos I want. It (the other system)
suffers no major glitch, AFAIK.
# STEPS TO REPRODUCE (might not work on different system - read further for
why I believe it is necessary to report nevertheless):
- Play a partially corrupt video file (I provided two in the attachment) with
Totem and wait. I believe - but I am not sure - that stressing the application
(for example, dragging the video scroller while the video plays) increases the
likeliness of visual artifacts appearing. Usually, the green-at-the-top and
red-at-the-bottom appear quite easily, the rest comes by letting the whole
thing run in the background for a few minutes, maybe a few hours at most (never
took up to an hour on my side).
# WHY I THINK IT'S AN IMPORTANT ISSUE (but not a "security issue" per se) :
The entire operating system was rendered unresponsive. While some visual cues
appearing on the video may hint that everything isn't right, if you were
working on something while the video plays and it crashes, you lost everything
you were doing back to the last point you saved. I also believe - though I
could be wrong - the the Kernel was dead as well, since REISUB doesn't work, as
mentioned earlier.
The bug shows it is possible for an ordinary application to cause a
complete denial of service on the whole system. No matter what the
problem inside Totem is, it has the power to creep down to the whole
system (and maybe the kernel); an application running in user space
shouldn't have such power.
However, I struggled to find clear, easily reproducible steps that could
result in a crash 100% of the time on any Ubuntu 18.04.4 LTS system. I
therefore cannot guarantee it isn't just a problem on my end (but even
if it is, I would like to understand how a bug in Totem can have such a
huge impact).
If my reasoning is wrong, then I apologize for the inconvenience. Feel
free to classify my report the way it should be if need there is.
# FILES ATTACHED :
- 2020-04-09 01-04-59.mp4 : (I apologize for the unprofessional video... I
tested it on a meme) A recording made with OBS of the apparition of the visual
artifacts. The artifacts are essentially concentrated in the first minute of
the video - the rest shows only the red/green gradients, which are still
disturbing but much less aggressive on the eye. At the very end of the video, I
close the target file and re-open it; fatal decision, it was at that moment
that my computer roze and stopped responding. A few moments later, the screen
went black, and showed the strange noise vision I described earlier and that I
show in the other video file.
- video20200409_011018907.mp4 : The other video file, recorded this time with
my phone, showing the screen once it has switched to it's "noisy" state
described earlier. There was no sound playing from the speakers, so I recorded
with no sound (thanks Ubuntu Touch for that option). Also, my mouse froze after
some time.
- Screenshot from 2020-04-09 01-15-02.png : When re-playing the video file
(which was obviously partly corrupt, since OBS crashed with the system before
it could stop recording), I noticed the artifacts came back rather quickly.
This time I only took a screenshot and immediately closed Totem, fearing
another full system crash.
- Folder "corrupt-but-playable" : It contains two video files which have
triggered the visual artifacts.
- y8gVYBC4jPyr8QB1.mp4 : The video you can see in the test crash.
- 2020-04-09 01-04-59.flv : The original, "corrupt" version of the MP4
with the same name (first in this list). Apart from having triggered the visual
artifacts, I also notice Totem couldn't compute its duration properly (I blame
the file for that, not Totem). Thankfully, OBS offers an option to remux
recordings, which converted the file to an MP4 that seems clean.
# SYSTEM INFO
- lsb_release -rd
Description: Ubuntu 18.04.4
LTS Release: 18.04
- uname -a
Linux desktop-u 5.3.0-46-generic #38~18.04.1-Ubuntu SMP Tue Mar 31 04:17:56
UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
- apt-cache policy totem
totem:
Installed: 3.26.0-0ubuntu6.2
Candidate: 3.26.0-0ubuntu6.2
Version table:
*** 3.26.0-0ubuntu6.2 500
500 http://ca.archive.ubuntu.com/ubuntu bionic-updates/main amd64
Packages
100 /var/lib/dpkg/status
3.26.0-0ubuntu6 500
500 http://ca.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
I'm open at reproducing the bug on my computer, on request, if more
information is needed.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: libgstreamer1.0-0 1.14.5-0ubuntu1~18.04.1
ProcVersionSignature: Ubuntu 5.3.0-46.38~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-46-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.14
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Apr 9 01:23:53 2020
InstallationDate: Installed on 2019-08-28 (224 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64
(20190805)
ProcEnviron:
LANGUAGE=en_CA:en
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_CA.UTF-8
SHELL=/bin/bash
SourcePackage: gstreamer1.0
UpgradeStatus: No upgrade log present (probably fresh install)
XorgLog: Error: [Errno 2] No such file or directory: '/var/log/Xorg.0.log'
+ ---
+ ProblemType: Bug
+ ApportVersion: 2.20.9-0ubuntu7.14
+ Architecture: amd64
+ AudioDevicesInUse:
+ USER PID ACCESS COMMAND
+ /dev/snd/controlC0: semphris 2027 F.... pulseaudio
+ /dev/snd/controlC1: semphris 2027 F.... pulseaudio
+ CurrentDesktop: ubuntu:GNOME
+ DistroRelease: Ubuntu 18.04
+ InstallationDate: Installed on 2019-08-28 (224 days ago)
+ InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64
(20190805)
+ MachineType: HP 260-p009
+ Package: linux (not installed)
+ ProcFB: 0 radeondrmfb
+ ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.3.0-46-generic
root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=1
+ ProcVersionSignature: Ubuntu 5.3.0-46.38~18.04.1-generic 5.3.18
+ RelatedPackageVersions:
+ linux-restricted-modules-5.3.0-46-generic N/A
+ linux-backports-modules-5.3.0-46-generic N/A
+ linux-firmware 1.173.17
+ Tags: bionic
+ Uname: Linux 5.3.0-46-generic x86_64
+ UpgradeStatus: No upgrade log present (probably fresh install)
+ UserGroups: sudo vboxusers
+ WifiSyslog:
+
+ _MarkForUpload: True
+ dmi.bios.date: 03/10/2016
+ dmi.bios.vendor: AMI
+ dmi.bios.version: F.03
+ dmi.board.asset.tag: CNV6190N2W
+ dmi.board.name: 81B4
+ dmi.board.vendor: HP
+ dmi.board.version: 01
+ dmi.chassis.asset.tag: CNV6190N2W
+ dmi.chassis.type: 3
+ dmi.chassis.vendor: HP
+ dmi.modalias:
dmi:bvnAMI:bvrF.03:bd03/10/2016:svnHP:pn260-p009:pvr:rvnHP:rn81B4:rvr01:cvnHP:ct3:cvr:
+ dmi.product.family: 103C_53316J G=D
+ dmi.product.name: 260-p009
+ dmi.product.sku: V8P62AA#ABL
+ dmi.sys.vendor: HP
** Attachment added: "AlsaInfo.txt"
https://bugs.launchpad.net/bugs/1871766/+attachment/5350421/+files/AlsaInfo.txt
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https://bugs.launchpad.net/bugs/1871766
Title:
Totem : Playing a corrupt video can result in full system crash -
Linux Kernel unresponsive
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