Under some circumstances, content from one Firefox window hidden behind another leaks onto the top one. Reproducible in both Bionic (with Intel graphics) and Disco (in a VirtualBox VM), reporting this from Disco.

== Steps to reproduce ==
1. Open one Firefox window, drag it to the right side of screen to fill the right half, and navigate to https://www.twitch.tv/rifftrax
2. Open another Firefox window, maximize it on top of the first one, and use this topmost window to open https://www.youtube.com/watch?v=P5dxd-ocaE8 and expand the Youtube view to ’theatre’ mode

== What happens ==
White parts of content in Firefox window #1 cast a spectral shadow on the black parts of content in Firefox window #2. It’s quite subtle, but luckily can be caught in screenshots: see attachments below. Pausing the Youtube video seems to make the effect to go away (the transparency disappears).

== What I’d expect to happen ==
For the topmost window to be completely opaque, i.e. not to see anything from behind the topmost window whether the video is playing or not.

== Other info ==
Though I don’t think this is tied the two sites I’ve used as an example, they’re the first and only ones I’ve happened to encounter this with. I’ve yet to find other reports about this, apart from one /r/Fedora thread mentioning something similar: https://www.reddit.com/r/Fedora/comments/7m9m4h/youtube_videos_are_transparent_kind_of_in_firefox/

Untouched screenshot of top window revealing content from another window below

Same screenshot with added hints about see-through content

I’ve hit an issue, which I believe I’ve now isolated to have come from upgrading fontconfig (and related packages) from 2.12.6-0ubuntu2 to 2.12.6-0ubuntu2.3 from -proposed: if I start Firefox and afterwards start Gparted or Synaptic, Firefox starts eating up all of my CPU. Eventually all letters in the Gparted/Synaptic UI turn into boxes.

Syslog typically then says something like below:

Dec 4 13:41:50 saegusa synaptic.desktop[30027]: (synaptic:30028): Pango-WARNING **: 13:41:50.995: failed to create cairo scaled font, expect ugly output. the offending font is ’DejaVu Sans 11′
Dec 4 13:41:50 saegusa synaptic.desktop[30027]: (synaptic:30028): Pango-WARNING **: 13:41:50.995: font_face status is: out of memory
Dec 4 13:41:50 saegusa synaptic.desktop[30027]: (synaptic:30028): Pango-WARNING **: 13:41:50.995: scaled_font status is: out of memory
Dec 4 13:41:50 saegusa synaptic.desktop[30027]: (synaptic:30028): Pango-WARNING **: 13:41:50.995: shaping failure, expect ugly output. shape-engine=’PangoFcShapeEngine’, font=’DejaVu Sans 11′, text=’Päivitä’
Dec 4 13:41:51 saegusa synaptic.desktop[30027]: (synaptic:30028): Pango-WARNING **: 13:41:51.007: failed to create cairo scaled font, expect ugly output. the offending font is ’DejaVu Sans 11’
Dec 4 13:41:51 saegusa synaptic.desktop[30027]: (synaptic:30028): Pango-WARNING **: 13:41:51.007: font_face status is: out of memory
Dec 4 13:41:51 saegusa synaptic.desktop[30027]: (synaptic:30028): Pango-WARNING **: 13:41:51.007: scaled_font status is: out of memory

The computer has 32 GB of memory and there’s plenty still usable when this occurs, so the OOM seems incorrect to me.

To be sure, I rolled back entirely from -proposed (which caused the issue to go away), then re-enabled -proposed and upgraded just fontconfig, and the issue reappeared.

Thanks Olivier, I’ve now added the link to my upstream report.

LO 1:6.0.6-0ubuntu0.18.04.1 in Bionic is likewise affected, and the workaround also works here.

This happens in 18.04 too. Bug #1650076 does also, and I’m not 100 % sure if these are two different issues or the same. I was able to reproduce #1650076 with the steps listed there, but just before that I had Evince following my scroll wheel despite being unfocussed, and I had not selected anything in the PDF before that (at least not knowingly). I haven’t found the steps to reproduce this without the selection though.

When acpica-tools is not installed, running acpidump or acpixtract produces no suggestions (in either Bionic or Cosmic):

$ acpixtract
acpixtract: command not found
$ apt-cache policy acpitools-ca
N: Unable to locate package acpitools-ca
$ apt-cache policy acpica-tools
acpica-tools:
Installed: (none)
Candidate: 20180629-1
Version table:
20180629-1 500
500 http://archive.ubuntu.com/ubuntu cosmic/universe amd64 Packages
$ sudo apt install acpica-tools
[sudo] password for jani:
Reading package lists… Done
Building dependency tree
Reading state information… Done
The following packages were automatically installed and are no longer required:
linux-headers-4.18.0-8 linux-headers-4.18.0-8-generic linux-image-4.18.0-8-generic linux-modules-4.18.0-8-generic
linux-modules-extra-4.18.0-8-generic
Use ’sudo apt autoremove’ to remove them.
The following NEW packages will be installed:
acpica-tools
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 851 kB of archives.
After this operation, 2782 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu cosmic/universe amd64 acpica-tools amd64 20180629-1 [851 kB]
Fetched 851 kB in 1s (1622 kB/s)
Selecting previously unselected package acpica-tools.
(Reading database … 207563 files and directories currently installed.)
Preparing to unpack …/acpica-tools_20180629-1_amd64.deb …
Unpacking acpica-tools (20180629-1) …
Setting up acpica-tools (20180629-1) …
update-alternatives: using /usr/bin/acpixtract-acpica to provide /usr/bin/acpixtract (acpixtract) in auto mode
update-alternatives: warning: skip creation of /usr/share/man/man1/acpixtract.1.gz because associated file /usr/share/man/man1/acpixtract-acpica.1 (of link group acpixtract) doesn’t exist
update-alternatives: using /usr/bin/acpidump-acpica to provide /usr/bin/acpidump (acpidump) in auto mode
update-alternatives: warning: skip creation of /usr/share/man/man1/acpidump.1.gz because associated file /usr/share/man/man1/acpidump-acpica.1 (of link group acpidump) doesn’t exist
Processing triggers for man-db (2.8.4-2) …
$ acpidump
Could not open table file: /sys/firmware/acpi/tables/SSDT
Could not get ACPI tables, AE_ACCESS
$ acpixtract

Intel ACPI Component Architecture
ACPI Binary Table Extraction Utility version 20180629
Copyright (c) 2000 – 2018 Intel Corporation

Usage: acpixtract [option] <InputFile>
Options:
-a Extract all tables, not just DSDT/SSDT
-f Force extraction, even if there are errors
-l List table summaries, do not extract
-m Extract multiple DSDT/SSDTs to a single file
-s <signature> Extract all tables with <signature>
-v Display version information
-vd Display build date and time

Extract binary ACPI tables from text acpidump output
Default invocation extracts the DSDT and all SSDTs

I’m seeing memory-related crashes when playing videos sliced (with ffmpeg -c copy) from mp4 streams (downloaded with youtube-dl). I’m attaching a sample clip which, granted, is pretty useless for a video, but which produces these crashes with 100% certainty for me; I just edited it down to a reasonable size and non-infringing content.

The errors reported just before core is dumped are (mostly) ”double free or corruption (fasttop)” or (less often) ”malloc_consolidate(): invalid chunk size”.

To be clear, my expectation here is not for the problematic clips to have useful content, or even to play back; just that vlc didn’t crash. (Totem for instance does not seem to crash with the same files.)

I’ll attach logs for both the double free and malloc_consolidate cases (which I’m producing by running LC_ALL=C vlc -vvv out.mp4 in a loop).

== The issue ==
Search and text selection highlighting visuals get mismatched with the actual selection in view-source when the value of `layout.css.devPixelsPerPx` is 1.2 or larger.

== Steps to reproduce ==
* Open `about:config`, find `layout.css.devPixelsPerPx` and change the value from default (-1.0) to 1.2.
* Open a view-source view with long lines: `view-source:https://www.youtube.com/user/10asti10`
* hit Ctrl+f, search for rss
* using the LMB, try selecting some text, then copy and paste it somewhere

== What happens ==
Screenshot 1: the highlighted text on the page is not ”rss”. The highlight doesn’t even adhere to letter widths.

Screenshot 2: the pasted text is not even close to what you’ve selected to copy.

== What I expect to happen ==
For the search to hightlight an occurence of ”rss”, and for the pasted text to correspond to what I’ve selected from the view-source view.

== Other info ==
* In my testing, a devPixelsPerPx value of 1.1 seems to not trigger this, whereas 1.2 and anything above does.
* In addition to 18.04 (whence the attached info is from) I’ve reproduced this in a VM running up-to-date 18.10.

Needless verbosity is the problem here, IMO. I’d expect to receive output from the installer only when the download or install fails for some reason, not when it succeeds.

(Also, to me the culprit here seems to be flashplugin-installer and not update-notifier, as plenty of other packages also report their installation progress, but only flashplugin’s seems to get forwarded to root’s mail even when nothing abnormal occurs.)

All right. Thanks, Jeremy!