When having set the BFQ io-scheduler as the default scheduler emerge/ebuild hangs at the end of the qmerge phase in an epoll_wait(3, ...) system call indefinitely. Reproducible: Always Steps to Reproduce: 1.boot a kernel built from gentoo-sources-3.12.0 with BFQ io-scheduler set as default 2.try to emerge any package 3. Actual Results: The ebuild hangs at the end of the qmerge phase indefinitely. Expected Results: No hang! emerge --info Portage 2.2.7 (default/linux/amd64/13.0/desktop/gnome, gcc-4.7.3, glibc-2.17, 3.12.0-tom_3 x86_64) ================================================================= System uname: Linux-3.12.0-tom_3-x86_64-Intel-R-_Core-TM-_i7_CPU_920_@_2.67GHz-with-gentoo-2.2 KiB Mem: 6107372 total, 3864168 free KiB Swap: 6399996 total, 6399996 free Timestamp of tree: Wed, 20 Nov 2013 07:15:01 +0000 ld GNU ld (GNU Binutils) 2.23.2 distcc 3.1 x86_64-pc-linux-gnu [disabled] ccache version 3.1.9 [disabled] app-shells/bash: 4.2_p45 dev-java/java-config: 2.2.0::java-overlay dev-lang/python: 2.7.5-r4, 3.2.5-r3, 3.3.2-r2 dev-util/ccache: 3.1.9-r3 dev-util/cmake: 2.8.12.1-r1 dev-util/pkgconfig: 0.28 sys-apps/baselayout: 2.2 sys-apps/openrc: 0.12.4 sys-apps/sandbox: 2.6-r1 sys-devel/autoconf: 2.13, 2.69 sys-devel/automake: 1.4_p6-r1, 1.9.6-r3, 1.10.3, 1.11.6, 1.12.6, 1.13.2, 1.14 sys-devel/binutils: 2.23.2 sys-devel/gcc: 4.6.4, 4.7.3-r1, 4.8.2 sys-devel/gcc-config: 1.8 sys-devel/libtool: 2.4.2 sys-devel/make: 3.82-r4 sys-kernel/linux-headers: 3.11 (virtual/os-headers) sys-libs/glibc: 2.17 Repositories: gentoo local zugaina science ramereth kde-sunset eva eyolfson bitcoin ladi bangert java-overlay proaudio tmacedo amielke-overlay retroshare-overlay sunrise foo-overlay maggu2810-overlay gentoo-zh roslin gentoo-haskell Krontage armagetron ACCEPT_KEYWORDS="amd64 ~amd64" ACCEPT_LICENSE="* -@EULA" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-O2 -march=native -msse4.1 -pipe -ggdb" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/config /usr/share/gnupg/qualified.txt /usr/share/maven-bin-3.0/conf /usr/share/maven-bin-3.1/conf /usr/share/polkit-1/actions /var/bind /var/lib/hsqldb" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/php/apache2-php5.4/ext-active/ /etc/php/apache2-php5.5/ext-active/ /etc/php/cgi-php5.4/ext-active/ /etc/php/cgi-php5.5/ext-active/ /etc/php/cli-php5.4/ext-active/ /etc/php/cli-php5.5/ext-active/ /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo /etc/texmf/language.dat.d /etc/texmf/language.def.d /etc/texmf/updmap.d /etc/texmf/web2c" CXXFLAGS="-O2 -march=native -msse4.1 -pipe -ggdb" DISTDIR="/usr/portage/distfiles" EMERGE_DEFAULT_OPTS="--jobs --load-average=10 --with-bdeps y" FCFLAGS="-O2 -pipe" FEATURES="assume-digests binpkg-logs compressdebug config-protect-if-modified distlocks ebuild-locks fixlafiles installsources merge-sync news parallel-fetch preserve-libs protect-owned sandbox sfperms splitdebug strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr" FFLAGS="-O2 -pipe" GENTOO_MIRRORS="ftp://gentoo.inode.at/source http://gentoo.inode.at ftp://ftp-stud.fht-esslingen.de/pub/Mirrors/gentoo/" LANG="en_US.UTF-8" LDFLAGS="-Wl,-O1 -Wl,--as-needed" MAKEOPTS="-j8" PKGDIR="/usr/portage/packages" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage /var/lib/layman/zugaina /var/lib/layman/science /var/lib/layman/ramereth /var/lib/layman/kde-sunset /var/lib/layman/eva /var/lib/layman/eyolfson /var/lib/layman/bitcoin /var/lib/layman/ladi /var/lib/layman/bangert /var/lib/layman/java-overlay /var/lib/layman/pro-audio /var/lib/layman/tmacedo /var/lib/layman/amielke-overlay /var/lib/layman/retroshare-overlay /var/lib/layman/sunrise /var/lib/layman/foo-overlay /var/lib/layman/maggu2810-overlay /var/lib/layman/gentoo-zh /var/lib/layman/roslin /var/lib/layman/haskell /var/lib/layman/krontage /var/lib/layman/armagetron" SYNC="rsync://rsync1.at.gentoo.org/gentoo-portage" USE="X a52 aac aalib acl acpi alsa amd64 amr apache2 avahi avi bash-completion berkdb bitmap-fonts bluetooth branding bzip2 cairo caps cdda cdr cli clutter colord cpdflib cracklib crypt css cuda cups curl curlwrappers cxx dba dbus dga dio divx4linux dri dts dv dvd dvdr dvdread eds emboss encode evo exif fam ffmpeg fftw firefox flac flash foomaticdb fortran ftp fuse gconf gd gdbm gif glitz gmp gnome gnome-keyring gnome-online-accounts gphoto2 gpm gstreamer gtk gtk2 gtk3 gtkhtml iconv icu ieee1394 imagemagick imap imlib introspection ipv6 jack java java6 javascript jpeg kipi ladspa lcms ldap libcaca libnotify libsecret libvisual logrotate lzo mad matroska mbrola mime ming mmx mng modules mono mp3 mp4 mpeg mudflap multilib mysql nas nautilus ncurses networkmanager nls nptl nptlonly nvidia odbc ogg opengl openmp osc pam pango pcmcia pcre pdf pdflib php plotutils png pnp policykit ppds pulseaudio qt3support qt4 quicktime readline samba scanner sdl session sharedmem shotwell smartcard smp socialweb sockets sox speex spell sse sse2 ssl ssse3 startup-notification svg systemd tcpd theora threads tiff tracker truetype type1 udev udisks unicode upower usb userlocales utf8 v4l v4l2 vcd vdpau vhosts vorbis wifi win32codecs wxwidgets wxwindows x264 xattr xcb xinerama xml xml2 xrandr xulrunner xv xvid xvmc zeitgeist zlib zvbi" ABI_X86="64" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" APACHE2_MODULES="unixd actions authn_core authz_core alias auth_basic auth_digest authn_anon authn_dbd 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 dbd deflate dir disk_cache env expires ext_filter file_cache filter headers ident imagemap include info log_config logio mem_cache mime mime_magic negotiation proxy proxy_ajp proxy_balancer proxy_connect proxy_http rewrite setenvif so socache_shmcb speling status unique_id userdir usertrack vhost_alias" APACHE2_MPMS="event" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump author" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ubx" INPUT_DEVICES="evdev keyboard mouse" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="pdfimport" LINGUAS="en de" NGINX_MODULES_HTTP="access auth_basic autoindex browser charset empty_gif fastcgi geo gzip limit_conn limit_req map memcached proxy referer rewrite scgi split_clients ssi upstream_ip_hash userid uwsgi sub" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-4" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_2 python3_3" QEMU_USER_TARGETS="arm" RUBY_TARGETS="ruby19 ruby18" SANE_BACKENDS="pixma net" USERLAND="GNU" VIDEO_CARDS="nvidia" 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" USE_PYTHON="2.7 3.2 3.3" Unset: CPPFLAGS, CTARGET, INSTALL_MASK, LC_ALL, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS
Did you try without BFQ to confirm it is BFQ? Do you use the NVIDIA drivers?
Yes I have tried with the same kernel but with CFQ as default scheduler which didn't show the problem and yes I use nvidia-drivers-331.20.
Stop! It's not the BFQ scheduler. I rebooted again still on CFQ like the attempt before where the bug didn't show... and it hung again. Seems to be pretty nondeterministic to me. I'm trying to pinpoint this issue now for days and everytime I think I found the root cause and eliminated it it happens again. See https://bugs.gentoo.org/show_bug.cgi?id=491346 I'm sorry! Next time I will report the issue again when I've really found the root cause (I hope) and cannot track it back to one of my own modifications.
It also seems not to be nvidia-driver related because it also hangs when I shut down X and remove the nvidia mdoule from the kernel using rmmod.
I have tried a lot of kernel 3.12.0 variations now, from vanilla to fully patched with everything I could apply and stages inbetween, different configurations, etc... What I found out is that it only depends on the boot. On some boots it works on some it doesn't regardless of patches or configuration. When it works after a new boot it continues to work until shut down, when not, it will not work until shut down. I couldn't determine a pattern when it decides to be a "successful" boot. I will try the same procedure with a 3.11 kernel tomorrow so I can possibly pinpoint it at least to 3.12.
How did it go? Sounds like this is bug #487558?
