Gnome Shell crashes with SIGSEGV in get_top_visible_window_actor → meta_compositor_sync_stack → meta_stack_tracker_sync_stack → stack_tracker_sync_stack_later → call_later_func

[Teo]

Ubuntu 19.10, all updated, sporadically (both in terms of timing and as an app I use), the gnome session crashs and re-opened by itself after about 1 second. However, closing the apps I was using, so as to lose everything. Now, just happened I saved all the logs via gnome logs, of 2 episodes where the problem occurred. It happened at a distance of not even a quarter of an hour. It's happened at 16.35 and 16.48. In attached this log. I can see only "bluetoothd: Failed to set mode: Blocked through rfkill (0x12)" of relevant, in both times, but I don't know.

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It sounds like some part of the system has crashed. To help us find the cause of the crash please follow these steps:

1. Look in /var/crash for crash files and if found run:
    ubuntu-bug YOURFILE.crash
Then tell us the ID of the newly-created bug.

2. If step 1 failed then look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

3. If step 2 also failed then apply the workaround from bug 994921, reboot, reproduce the crash, and retry step 1.

Please take care to avoid attaching .crash files to bugs as we are unable to process them as file attachments. It would also be a security risk for yourself.

[Teo (teo7)]

Ok, I found the crash file and i ran it through ubuntu-bug file.crash. Now, where is the id you are looking for?

[Teo (teo7)]

I obtained a stack and JS trace using GDB. File in attachment.
Then I ran "journalctl /usr/bin/gnome-shell -b0 | grep -A 30 "== Stack trace for context"" and this is the result -> https://pastebin.com/S2CuLPJ8

[Sebastien Bacher (seb128)]

Thanks for the debugging but the gdb backtrace is no real use without debug informations, could you install those following https://wiki.ubuntu.com/DebuggingProgramCrash#Installing_debug_symbols_manually ?
(or easier send the report using ubuntu-bug and give the ID as explained by Daniel)

[Daniel van Vugt (vanvugt)]

Teodoro, please follow step 2 in comment #2.

[Daniel van Vugt (vanvugt)]

That one is from gnome-boxes, not gnome-shell.

[Teo (teo7)]

Now, this looks like the real gnome-shell crash https://errors.ubuntu.com/oops/3371051e-2040-11ea-a702-fa163ee63de6

[Daniel van Vugt (vanvugt)]

Thanks, yes that looks like a real and clear crash in gnome-shell. I think bug 1857947 describes it best though so let's track it there.