Public bug reported: I wanted to report a gnome-shell bug with a backtrace, so tried to use the instructions in
https://wiki.gnome.org/Projects/GnomeShell/Debugging which say to do the following in a separate VT: gnome_session=$(pgrep -u $USER gnome-session) eval export $(sed 's/\o000/\n/g;' < /proc/$gnome_session/environ | grep DISPLAY) eval export $(sed 's/\o000/\n/g;' < /proc/$gnome_session/environ | grep XAUTHORITY) eval export $(sed 's/\o000/\n/g;' < /proc/$gnome_session/environ | grep DBUS_SESSION_BUS_ADDRESS) gdb ...etc... However three problems came up, two minor (wrong instructions), the other major: (1) There is more than one gnome-session process, and so the shell variable $gnome_session gets set to a list of several PIDs, which in turn causes syntax errors when using the expression "/proc/$gnome_session/environ". In Ubuntu 21.04 I have three gnome-session processes immediately after rebooting and logging in (I have auto-login enabled, so the login happens by itself, in case that matters): $ ps -F $(pgrep -u $USER gnome-session|perl -p -e 's/(\d+)/-p $1/') UID PID PPID C SZ RSS PSR STIME TTY TIME CMD jima 9743 9725 0 55216 16084 2 13:41 tty3 00:00:00 /usr/libexec/gnome-session-binary --systemd --session=ubuntu jima 9828 8066 0 24031 6148 8 13:41 ? 00:00:00 /usr/libexec/gnome-session-ctl --monitor jima 9838 8066 0 129272 18176 7 13:41 ? 00:00:00 /usr/libexec/gnome-session-binary --systemd-service --session=ubuntu (2) The instructions specify this gdb command: call gjs_dumpstack () However that results in an error and the call is not made: 'gjs_dumpstack' has unknown return type; cast the call to its declared return type (3) Most importantly, a crash: After after starting gdb in an independent VT to replace the running gnome-session process (or possibly at the moment I switched VTs back to where I could observe the gnome session), the session had immediately gotten a white screen with "Oh No... something went wrong..." forcing me log out. I swtiched back to the independent VT, typed Control-C to get control in gdb, and produced the backtraces (see attached typescript file). The attached typescript file shows what I did to circumvent the buggy instructions at https://wiki.gnome.org/Projects/GnomeShell/Debugging P.S. The original crash I wanted to report was that opening any .jpg in gimp and selecting part of the image and then doing Select->Invert instantly freezes the system. The only recovery is to use a separate VT to kill the gimp process, after which gnome-shell restarts. A system error dialog appears saying gnome-session [correction: gnome-shell] got a segfault somewhere; thus the desire to get a backtrace. But this bug report is _not_ about that bug, at least not explicitly; it is about how using the debug instructions in the wiki seem to cause a crash on their own. ProblemType: Bug DistroRelease: Ubuntu 21.04 Package: gnome-shell 3.38.4-1ubuntu3~21.04.1 ProcVersionSignature: Ubuntu 5.11.0-25.27-generic 5.11.22 Uname: Linux 5.11.0-25-generic x86_64 ApportVersion: 2.20.11-0ubuntu65.1 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: GNOME Date: Sun Jul 25 13:41:54 2021 DisplayManager: gdm3 InstallationDate: Installed on 2021-07-20 (5 days ago) InstallationMedia: Ubuntu-Server 21.04 "Hirsute Hippo" - Release amd64 (20210421) RelatedPackageVersions: mutter-common 3.38.4-1ubuntu2 SourcePackage: gnome-shell UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: gnome-shell (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug hirsute third-party-packages uec-images ** Attachment added: "typescript-processed" https://bugs.launchpad.net/bugs/1937958/+attachment/5513572/+files/typescript-processed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1937958 Title: gnome-shell gdb instructions cause immediate "Oh no" crash To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1937958/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
