Bug 320309 – dev-qt/qtcore: apps lock up after launching external applications

• Product: Gentoo Linux
• Status: RESOLVED CANTFIX

[Description Will Saxon 2010-05-18 02:54:26 UTC]

I upgraded from 0.22_p22860 to 0.22_p24255 as part of an "emerge -uND world system" run. After this upgrade, I notice that mythfrontend will frequently stop responding to input after closing external applications like Chrome or VLC (launched via MythBrowser and MythVideo plugins, respectively). The only way to get the Mythfrontend UI to work again is to kill the process and start over. 

This does not appear to affect X or other running programs - I use evilwm with this and am able to start an xterm to kill the mythfrontend process. I am also able to ctrl-alt-f1 to a console and kill the process that way. 

Reproducible: Always

Steps to Reproduce:
1. emerge mythtv with ~x86 keyword enabled
2. emerge mythvideo and/or mythbrowser
3. configure either to use an external application
4. use external application via plugin, then close and try to interact with mythfrontend.

Actual Results:  
mythfrontend is unresponsive

Expected Results:  
mythfrontend responds to input normally

Portage 2.1.8.3 (default/linux/x86/10.0, gcc-4.4.3, glibc-2.11-r1, 2.6.33-gentoo-r1 i686)
=================================================================
System uname: Linux-2.6.33-gentoo-r1-i686-Intel-R-_Celeron-R-_CPU_E3300_@_2.50GHz-with-gentoo-2.0.1
Timestamp of tree: Sat, 15 May 2010 15:45:03 +0000
app-shells/bash:     4.1_p5
dev-java/java-config: 2.1.10
dev-lang/python:     2.6.5-r1, 3.1.2-r2
dev-util/cmake:      2.8.1-r1
sys-apps/baselayout: 2.0.1
sys-apps/openrc:     0.6.1-r1
sys-apps/sandbox:    2.2
sys-devel/autoconf:  2.13, 2.65
sys-devel/automake:  1.9.6-r2, 1.10.3, 1.11.1
sys-devel/binutils:  2.20.1
sys-devel/gcc:       4.4.3
sys-devel/gcc-config: 1.4.1
sys-devel/libtool:   2.2.6b
virtual/os-headers:  2.6.33
ACCEPT_KEYWORDS="x86 ~x86"
ACCEPT_LICENSE="* -@EULA dlj"
CBUILD="i686-pc-linux-gnu"
CFLAGS="-O3 -march=native -pipe"
CHOST="i686-pc-linux-gnu"
CONFIG_PROTECT="/etc /home/mythtv/ /usr/share/X11/xkb"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/env.d/java/ /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo"
CXXFLAGS="-O3 -march=native -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="assume-digests distlocks fixpackages news parallel-fetch protect-owned sandbox sfperms strict unmerge-logs unmerge-orphans userfetch"
GENTOO_MIRRORS="http://gentoo.chem.wisc.edu/gentoo"
LDFLAGS="-Wl,-O1"
LINGUAS="en en_US"
MAKEOPTS="-j2"
PKGDIR="/usr/portage/packages"
PORTAGE_CONFIGROOT="/"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
SYNC="rsync://rsync21.us.gentoo.org/gentoo-portage"
USE="X a52 aac acl acpi alsa autostart berkdb bzip2 cairo caps cleartype cli cracklib crypt ctype cxx dbus dri dvb dvd encode extras fftw filter flac gallium gdbm git gpm hardcoded-tables iconv imagemagick ipv6 joystick jpeg json lcd libvisual lirc mjpeg mmap mmx mmxext modules mp3 mpeg mudflap mysql ncurses nls nptl nptlonly nsplugin ogg opengl openmp openssl pam pch pcre perl png posix pppd python qt3support readline reflection sdl session spl sse sse2 ssl ssse3 subversion svg symlink sysfs tcpd theora threads tiff truetype unicode v4l2 vim-syntax vorbis win32codecs x264 x86 xorg xv xvid zlib" ALSA_CARDS="hda-intel" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mmap_emul mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" APACHE2_MPMS="worker" ELIBC="glibc" INPUT_DEVICES="evdev" KERNEL="linux" LCD_DEVICES="irtrans" LINGUAS="en en_US" RUBY_TARGETS="ruby18" USERLAND="GNU" VIDEO_CARDS="intel" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account"
Unset:  CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, FFLAGS, INSTALL_MASK, LANG, LC_ALL, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, PORTDIR_OVERLAY

[Comment 1 Doug Goldstein (RETIRED) 2010-06-13 07:54:42 UTC]

Turns out this is actually a bug in Qt. See http://bugreports.qt.nokia.com/browse/QTBUG-5990 for more details

[Comment 2 Doug Goldstein (RETIRED) 2010-06-13 07:56:19 UTC]

*** Bug 314877 has been marked as a duplicate of this bug. ***

[Comment 3 Michael Palimaka (kensington) 2013-03-10 13:01:45 UTC]

There is a patch on the upstream bug, I am not sure if it is useful or not though?

[Comment 4 Davide Pesavento (RETIRED) 2013-03-10 18:58:37 UTC]

(In reply to comment #3)
> There is a patch on the upstream bug, I am not sure if it is useful or not
> though?

By default I don't trust a patch that upstream never commented on.

[Comment 5 Michael Palimaka (kensington) 2015-10-09 14:08:43 UTC]

There's no further Qt 4 releases planned.

[Comment 6 Davide Pesavento (RETIRED) 2015-10-09 14:32:40 UTC]

A more correct resolution would be CANTFIX, given that:

(a) upstream abandoned a possible patch that was targeted to the stable branch, and could have been backported to 4.8, because there were doubts about its usefulness (https://codereview.qt-project.org/61294)

(b) since 5.5 Qt uses forkfd, which doesn't suffer from this bug, however it's not possible to backport the forkfd implementation to 4.8