Can you please try to obtain a backtrace according to https://fedoraproject.org/wiki/Debugging_guidelines_for_Mozilla_products#Application_crash ?

That fails as I described in bug 
https://bugzilla.redhat.com/show_bug.cgi?id=1676331#c3

I've reproduced the bug in qemu-kvm using virt-manager, although it's more difficult to reproduce, maybe 1 in 10 attempts. I left gdb running for 11 hours and still "crash_bt" file is zero bytes; I've done 'coredumpctl gdb' on firefox coredumps before and they take maybe a minute.

Please install this build when it's done - https://koji.fedoraproject.org/koji/buildinfo?buildID=1217476 - and try to attach ABRT report of the crash. Thanks.

Feb 28 16:28:51 flap.local firefox-wayland.desktop[1688]: Exiting due to channel error.
Feb 28 16:28:51 flap.local firefox-wayland.desktop[1688]: Crash Annotation GraphicsCriticalError: |[C0][GFX1-]: Receive IPC close with reason=AbnormalShutdown (t=35.7221) [>
Feb 28 16:28:51 flap.local firefox-wayland.desktop[1688]: Exiting due to channel error.
Feb 28 16:28:51 flap.local firefox-wayland.desktop[1688]: [Child 3908, Chrome_ChildThread] WARNING: pipe error (33): Connection reset by peer: file /builddir/build/BUILD/fi>
Feb 28 16:28:51 flap.local firefox-wayland.desktop[1688]: [Child 3908, Chrome_ChildThread] WARNING: pipe error (3): Connection reset by peer: file /builddir/build/BUILD/fir>
Feb 28 16:28:51 flap.local firefox-wayland.desktop[1688]: Exiting due to channel error.
Feb 28 16:28:52 flap.local systemd-coredump[4117]: Process 3782 (firefox) of user 1000 dumped core.
[snipped stack trace due to length]                                              
Feb 28 16:28:53 flap.local abrtd[811]: Size of '/var/spool/abrt' >= 5000 MB (MaxCrashReportsSize), deleting old directory 'ccpp-2019-02-14-19:37:06.612833-11893'
Feb 28 16:28:54 flap.local abrt-server[4124]: Package 'firefox' isn't signed with proper key
Feb 28 16:28:54 flap.local abrt-server[4124]: 'post-create' on '/var/spool/abrt/ccpp-2019-02-28-16:28:53.316936-3782' exited with 1
Feb 28 16:28:54 flap.local abrt-server[4124]: Deleting problem directory '/var/spool/abrt/ccpp-2019-02-28-16:28:53.316936-3782'

I'm trying to process this coredump file with `coredumpctl gdb`...

Created attachment 1539673 [details]
coredumpctl info

Ok so processing that coredump file with `coredump gdb` fails also, it loads symbols, gets to the segmentation fault, and that's it, gdb and kswapd0 hog the system and turn it into an unusable hair dryer. But I have a coredump file.

61MB LZ4
https://drive.google.com/open?id=1JVzM26Qy3CfynAT_1vELvSlZWQdEcq9V

I see. That may be caused by the PGO+LTO optimization enabled for F28/29. I'll produce a build without those optimizations.

New test builds are here, I hope the debug setup goes through koji - https://koji.fedoraproject.org/koji/taskinfo?taskID=33114131

Anyway, from the backtrace you posted it looks like the bug happens in gtk_im_context module - I'll try to find related parts in widget/gtk. Thanks!

My candidate is gtk_im_context_set_surrounding() call from IMContextWrapper.cpp but I'd need more detailed trace to be sure.

Can you please try this build? https://koji.fedoraproject.org/koji/taskinfo?taskID=33114171
It has disabled PGO/LTO and upstream crash reporter, ABRT should catch the crash. Also don't forget to install debuginfo packages from this build.
Thanks.

Created attachment 1539885 [details]
crash_bt

OK super I think this worked finally.

1.
$ firefox-wayland --name ffwayland --safe-mode --ProfileManager
2.
Choose a "test" profile that's clean (no settings changes from defaults)
3.
Trigger the crash
4.
In the console I see
Type 'gdb /usr/lib64/firefox/firefox 16008' to attach your debugger to this thread.
So I go do that in a separate shell
5.
collect crash_bt file as described in the debugging guidelines for mozilla products wiki, and that's the file attached.

Great, Thanks!

Hm, I'm still unable to reproduce. Do you run any special desktop localization (locale), any special GTK input module? (GTK_IM_MODULE) What does print "gsettings get org.gnome.desktop.interface gtk-im-module" on console?

(In reply to Martin Stransky from comment #15)
> Hm, I'm still unable to reproduce. Do you run any special desktop
> localization (locale), any special GTK input module? (GTK_IM_MODULE)

$ gsettings get org.gnome.desktop.interface gtk-im-module
'ibus'

$ locale
LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

However, as mentioned in comment 3, I was able to reproduce in a VM booted with Workstation Live ISO. I just tried this again with 20190326 compose of Workstation Live which has Firefox 66.0.1-1 and can't reproduce it there after manually installing Firefox-Wayland in the live environment.

Back on baremetal, which has firefox-66.0.1-1.fc30.x86_64, I also can no longer get a crash. However, if the initial cursor placement point is out of the display area, I must double click to get a selection. e.g.

1. click to place cursor in body of text
2. scroll so the cursor is no longer visible
3. shift+click does nothing
4. 2nd shift+click selects range of text

whereas if I skip step 2, cursor is visible, shift+click selects range on the first try. Seems plausible this is related to the crash, where shift+click with a non-visible cursor is somehow causing confusion, before it was crashing and now its behaving as a one time no op.

(In reply to Chris Murphy from comment #16)
> 1. click to place cursor in body of text
> 2. scroll so the cursor is no longer visible
> 3. shift+click does nothing
> 4. 2nd shift+click selects range of text

This behavior happens with Firefox and Firefox Wayland.

Also, I just realized the crashers were always on Fedora 29. I'm not certain I tested on Fedora 30 until now.

OK back on Fedora 29, update to
firefox-66.0.1-1.fc29.x86_64
firefox-wayland-66.0.1-1.fc29.x86_64

And ffwayland still crashes:

1. click to place cursor in body of text
2. scroll so the cursor is no longer visible
3. shift+click does nothing immediately, but in about 2-3 seconds it crashes

Created attachment 1549183 [details]
ffwayland coredumpctl info

firefox-wayland-66.0.1-1.fc29.x86_64

I suspect it's https://bugzilla.mozilla.org/show_bug.cgi?id=1539773 which is already fixed in Fedora 30. May be also reason I can't reproduce it here.

Confirmed that control-a and right-click select all also cause the crash. Koji has gtk3 3.24.3-1 for fc29, but bodhi says it was obsoleted by 3.24.1-2.

Please can you try F30 when you get a chance? It may be also related to different input method/module. Thanks.

I haven't seen this problem since upgraded to Fedora 30, it's been a couple months at least.

Great, Thanks.