Bug 1520010

Created attachment 1361853 [details]
File: backtrace

Created attachment 1361854 [details]
File: cgroup

Created attachment 1361855 [details]
File: core_backtrace

Created attachment 1361856 [details]
File: cpuinfo

Created attachment 1361857 [details]
File: dso_list

Created attachment 1361858 [details]
File: environ

Created attachment 1361859 [details]
File: limits

Created attachment 1361860 [details]
File: maps

Created attachment 1361861 [details]
File: mountinfo

Created attachment 1361862 [details]
File: open_fds

Created attachment 1361863 [details]
File: proc_pid_status

Created attachment 1361864 [details]
File: var_log_messages

*** Bug 1522958 has been marked as a duplicate of this bug. ***

*** Bug 1536076 has been marked as a duplicate of this bug. ***

*** Bug 1540602 has been marked as a duplicate of this bug. ***

*** Bug 1542698 has been marked as a duplicate of this bug. ***

Had this twice already. Tried opening Gnome Software from the Dash and then my session crashed.

Similar problem has been detected:

1) Press the Super key to bring up the Activites view
2) Type the word "font"

My enabled search providers are Boxes, Calculator, Characters, Clocks, Contacts, Files, Notes, Passwords and Keys, Software, Terminal, and Web.
I have gnome-shell extensions disabled, and I am using the default theme.

reporter:       libreport-2.9.3
backtrace_rating: 4
cmdline:        /usr/bin/gnome-shell
crash_function: gtk_icon_info_load_icon_finish
executable:     /usr/bin/gnome-shell
journald_cursor: s=92bf442ed9ea4dd8be6b0cd7a66113a9;i=30d43;b=4f7c81e3c214469e9725a069a94d790e;m=3b940002a;t=565f681e86fcc;x=b894f68730cc5a9b
kernel:         4.15.3-300.fc27.x86_64
package:        gnome-shell-3.26.2-4.fc27
reason:         gnome-shell killed by SIGABRT
rootdir:        /
runlevel:       N 5
type:           CCpp
uid:            1000

*** Bug 1550839 has been marked as a duplicate of this bug. ***

Similar problem has been detected:

This is the third crash in the last 5 minutes. The first two I searched for Screenshot and got the crash when I clicked enter. 
In the third one (this one) it crashed even before clicking. 
I'm honestly not sure it this was the case for the first two as well because I usually press enter quite quickly after seeing the right answer to my query.

reporter:       libreport-2.9.3
backtrace_rating: 4
cmdline:        /usr/bin/gnome-shell
crash_function: gtk_icon_info_load_icon_finish
executable:     /usr/bin/gnome-shell
journald_cursor: s=a78f0a8d130a492b960d4a95283994ec;i=df5ea;b=698a4ec5726c4f9cbcfd00920e1d64a7;m=e7d2233f6;t=5668b875e7f4e;x=99ecba347a38e134
kernel:         4.15.4-300.fc27.x86_64
package:        gnome-shell-3.26.2-4.fc27
reason:         gnome-shell killed by SIGABRT
rootdir:        /
runlevel:       N 5
type:           CCpp
uid:            1000

I can reliably crash GNOME shell by typing "sc" in the search bar.

By exclusion, I can also tell you that the search provider causing the crash is Files. If I disable it everything seems fine.

This is a very annoying bug, so I will help fixing it. I managed to gdb into the crashing gnome-shell with the help of https://fedoraproject.org/wiki/How_to_debug_Wayland_problems .

See the attached gdb_2018_03_18_naive.txt for my first attempts of debugging this.

I have never dealt with gtk/gnome-shell etc, so I just do whatever you want me to do.

The crash happens here:
https://code.woboq.org/gtk/gtk/gtk/gtkicontheme.c.html#gtk_icon_info_load_icon_finish

With this GtkIconInfo icon_info:

$2 = {parent_instance = {g_type_instance = {g_class = 0x55855b2294d0}, ref_count = 3, qdata = 0x0}, key = {icon_names = 0x0, size = 0, scale = 0, flags = (unknown: 0)}, 
  in_cache = 0x0, filename = 0x55855b5c2a80 "/home/daniel/.cache/thumbnails/large/561114c38c138d4fcd5e62b89a9a23ae.png", icon_file = 0x7f3af506a460, 
  loadable = 0x7f3b800cb600, emblem_infos = 0x0, cache_pixbuf = 0x0, dir_type = ICON_THEME_DIR_UNTHEMED, dir_size = 24, dir_scale = 1, min_size = 0, max_size = 0, 
  desired_size = 24, desired_scale = 1, forced_size = 0, emblems_applied = 0, is_svg = 0, is_resource = 0, pixbuf = 0x0, proxy_pixbuf = 0x0, load_error = 0x0, 
  unscaled_scale = 1, scale = 0.47999999999999998, symbolic_pixbuf_cache = 0x0, symbolic_width = 0, symbolic_height = 0}

I've looked at the thumbnail and it is really only a 1x50 px light blue stripe.

Okay, gtk_icon_info_load_icon_finish() is somehow related to async functionality and updates its argument with the data that it retrieves from its async-task. For some reason that data is not ready.

YAA, I have an idea what is happening:

The task calls icon_info_ensure_scale_and_pixbuf() to load the image. That function somehow calculates a scaling factor, in this case scale = 0.47999999999999998. But the png image has a size of 1x50, so the call to gdk_pixbuf_scale_simple will get a width of 0.5+1*0.4799 which will round down to 0. I have not found the source of gdk_pixbuf_scale_simple, but I assume it will simply not allocate a pixbuf when one image dimension equals 0. This will then cause more trouble in gtk_icon_info_load_icon_finish when trying to move the pixbuf from the `dup` into the other icon_info, expecting that there is a pixbuf.

      icon_info->pixbuf = gdk_pixbuf_scale_simple (source_pixbuf,
                                                   0.5 + image_width * icon_info->scale,
                                                   0.5 + image_height * icon_info->scale,
GDK_INTERP_BILINEAR);

Conclusion: Some thumbnail generator generates thumbnails, that will cause trouble in gnome-shell.

Temporary workaround: Disable the Files search provider.

Hmm, that does not took too long to figure out :D

Daniel

Created attachment 1409471 [details]
GDB session

I notified gtk

https://gitlab.gnome.org/GNOME/gtk/issues/119

*** Bug 1564261 has been marked as a duplicate of this bug. ***

*** Bug 1568518 has been marked as a duplicate of this bug. ***

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