Description of problem: Crashes very soon after starting. Version-Release number of selected component: guvcview-2.0.8-6.fc39 Additional info: reporter: libreport-2.17.11 type: CCpp reason: guvcview killed by SIGSEGV journald_cursor: s=8629d2e1a34d4aa8a505c7a7b72ea5ac;i=1e7a9;b=a9a9c12df89246459aab8984036054fc;m=91465ce5f;t=60f6d1e16d407;x=ccab1a8775872d89 executable: /usr/bin/guvcview cmdline: guvcview cgroup: 0::/user.slice/user-1000.slice/user/app.slice/app-org.gnome.Terminal.slice/tmux-spawn-a0198cc8-4a35-4b26-a290-08e36c0119f7.scope rootdir: / uid: 1000 kernel: 6.6.11-200.fc39.x86_64 package: guvcview-2.0.8-6.fc39 runlevel: N 5 backtrace_rating: 4 crash_function: _gtk_css_value_compute comment: Crashes very soon after starting. Truncated backtrace: Thread no. 1 (15 frames) #0 _gtk_css_value_compute at ../gtk/gtkcssvalue.c:97 #1 gtk_css_value_position_compute at ../gtk/gtkcsspositionvalue.c:48 #2 gtk_css_value_array_compute at ../gtk/gtkcssarrayvalue.c:59 #3 gtk_css_static_style_compute_value at ../gtk/gtkcssstaticstyle.c:237 #4 _gtk_css_lookup_resolve at ../gtk/gtkcsslookup.c:122 #5 gtk_css_static_style_new_compute at ../gtk/gtkcssstaticstyle.c:195 #6 gtk_css_node_create_style at ../gtk/gtkcssnode.c:371 #7 gtk_css_node_real_update_style at ../gtk/gtkcssnode.c:425 #8 gtk_css_node_ensure_style at ../gtk/gtkcssnode.c:1007 #12 gtk_css_node_get_style at ../gtk/gtkcssnode.c:1033 #13 gtk_style_context_lookup_style at ../gtk/gtkstylecontext.c:494 #14 _gtk_style_context_peek_property at ../gtk/gtkstylecontext.c:1642 #15 gtk_widget_update_alpha at ../gtk/gtkwidget.c:16098 #16 gtk_widget_realize at ../gtk/gtkwidget.c:5541 #17 gtk_widget_set_parent at ../gtk/gtkwidget.c:9663
Created attachment 2021714 [details] File: proc_pid_status
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Created attachment 2021717 [details] File: open_fds
Created attachment 2021718 [details] File: mountinfo
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Created attachment 2021721 [details] File: core_backtrace
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Created attachment 2021723 [details] File: dso_list
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Created attachment 2021725 [details] File: environ
So, I can reproduce this, on two systems. There actually seem to be some different variations on the crash, but it always crashes soon after startup, when run as a regular user. It does *not* crash (for Matt Hartley, who pointed this out, or for me, at least) when run as root. The backtraces differ a bit, but always wind up running through the GTK CSS code.
Created attachment 2024079 [details] backtrace from one of my crashed attempts Here's the backtrace from one of my crashes. This is with 2.0.8. I have built 2.1.0 and confirmed that still crashes.
This is the "should not be reached" code we hit in my traceback, from GTK gtk/gtkcssinheritvalue.c : static void G_GNUC_NORETURN gtk_css_value_inherit_free (GtkCssValue *value) { /* Can only happen if the unique value gets unreffed too often */ g_assert_not_reached (); }
Here's some references of other projects that ran into this kinda crash: https://github.com/lutris/lutris/issues/5092 https://github.com/bottlesdevs/Bottles/issues/813 https://github.com/haskell-gi/haskell-gi/issues/117 it seems this tends to involve threading and memory management and destructors and other things I'm not any kind of expert on, so I'm not going to attempt a fix for this myself.
Upstream report: https://sourceforge.net/p/guvcview/tickets/76/
After further investigation, we suspect this is actually a GTK 3 issue. https://retrace.fedoraproject.org/faf/problems/bthash/?bth=610603e80cf6cdd99354b01975ab1a7b35ad2c50&bth=4a6c303b02b725b8e01f713e3fb4563a476b8e54&bth=c480691445209611ff5079e7be7a2b6a7d488f91&bth=dd80be01d4012f9a2db76faff2f768d77bec4d27&bth=69a7fcaf4179c04257b19a601d9ca079c5c7a803&bth=df920c604a2b926a04a80522743900a4653d85bf seems to be GNOME Connections running into the same thing. Filed https://gitlab.gnome.org/GNOME/gtk/-/issues/6611 . Neal is going to do a build which uses SFML instead of SDL. This seems to avoid the crashes, we think because it forces guvcview to run as an XWayland app (SFML does not have native Wayland support).
FEDORA-2024-ac9be9fa7b (guvcview-2.1.0-2.fc40) has been submitted as an update to Fedora 40. https://bodhi.fedoraproject.org/updates/FEDORA-2024-ac9be9fa7b
FEDORA-2024-ac9be9fa7b has been pushed to the Fedora 40 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2024-ac9be9fa7b` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2024-ac9be9fa7b See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
I've unlinked this bug from the guvcview update.
I think I remember mclasen suggesting somewhere that this may really be a libdecor issue...can't find the reference right now, though.
oh, https://gitlab.gnome.org/GNOME/gtk/-/issues/6611 . Asking for clarification there.
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This was *effectively* fixed by switching the backend to SFML in https://bodhi.fedoraproject.org/updates/FEDORA-2024-0249d1561b , which makes guvcview an XWayland app and avoids the bug. The underlying problem was reported to libdecor upstream in https://gitlab.freedesktop.org/libdecor/libdecor/-/issues/72 .