Bug 657924 – gnome-settings-daemon crashed with SIGSEGV in gnome_rr_screen_get_dpms_mode()

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Bug 657924 - gnome-settings-daemon crashed with SIGSEGV in gnome_rr_screen_get_dpms_mode()


Summary:	gnome-settings-daemon crashed with SIGSEGV in gnome_rr_screen_get_dpms_mode()


Status:	RESOLVED FIXED

Product:	gnome-settings-daemon
Classification:	Core
Component:	power
Version:	3.1.x
Hardware:	Other Linux

Importance:	Normal critical
Target Milestone:	---
Assigned To:	Richard Hughes
QA Contact:	gnome-settings-daemon-maint

URL:
Whiteboard:

Depends on:
Blocks:

Reported:	2011-09-01 12:38 UTC by Pedro Villavicencio
Modified:	2011-09-01 15:51 UTC

See Also:
GNOME target:	---
GNOME version:	3.1/3.2

Attachments
power: Do most of the work in _start () (5.00 KB, patch) 2011-09-01 15:32 UTC, Bastien Nocera	committed	Details \| Review

Description Pedro Villavicencio 2011-09-01 12:38:38 UTC

this report has been filed here:

https://bugs.launchpad.net/ubuntu/+source/gnome-desktop3/+bug/838670

".

+ Trace 228308

Thread 1 (Thread 0x7f10d9224940 (LWP 5133))

#0 gnome_rr_screen_get_dpms_mode
at gnome-rr.c line 1189
#1 gnome_rr_screen_set_dpms_mode
at gnome-rr.c line 1251
#2 do_lid_open_action
at gsd-power-manager.c line 2073
#3 up_client_changed_cb
at gsd-power-manager.c line 2160
#4 up_client_changed_cb
at gsd-power-manager.c line 2138
#5 g_closure_invoke
at /build/buildd/glib2.0-2.29.16/./gobject/gclosure.c line 773
#6 signal_emit_unlocked_R
at /build/buildd/glib2.0-2.29.16/./gobject/gsignal.c line 3271
#7 g_signal_emit_valist
at /build/buildd/glib2.0-2.29.16/./gobject/gsignal.c line 3002
#8 g_signal_emit
at /build/buildd/glib2.0-2.29.16/./gobject/gsignal.c line 3059
#9 marshal_dbus_message_to_g_marshaller
at dbus-gproxy.c line 1733
#10 g_closure_invoke
at /build/buildd/glib2.0-2.29.16/./gobject/gclosure.c line 773
#11 signal_emit_unlocked_R
at /build/buildd/glib2.0-2.29.16/./gobject/gsignal.c line 3271
#12 g_signal_emit_valist
at /build/buildd/glib2.0-2.29.16/./gobject/gsignal.c line 3002
#13 g_signal_emit
at /build/buildd/glib2.0-2.29.16/./gobject/gsignal.c line 3059
#14 dbus_g_proxy_emit_remote_signal
at dbus-gproxy.c line 1786
#15 dbus_g_proxy_manager_filter
at dbus-gproxy.c line 1353
#16 dbus_g_proxy_manager_filter
at dbus-gproxy.c line 1194
#17 dbus_connection_dispatch
from /tmp/tmp7WJOm_/lib/x86_64-linux-gnu/libdbus-1.so.3
#18 message_queue_dispatch
at dbus-gmain.c line 90
#19 g_main_dispatch
at /build/buildd/glib2.0-2.29.16/./glib/gmain.c line 2439
#20 g_main_context_dispatch
at /build/buildd/glib2.0-2.29.16/./glib/gmain.c line 3008
#21 g_main_context_iterate
at /build/buildd/glib2.0-2.29.16/./glib/gmain.c line 3086
#22 g_main_loop_run
at /build/buildd/glib2.0-2.29.16/./glib/gmain.c line 3294
#23 gtk_main
at /build/buildd/gtk+3.0-3.1.12/./gtk/gtkmain.c line 1367
#24 main
at main.c line 451

Comment 1 Federico Mena Quintero 2011-09-01 15:16:03 UTC

The problem is that the passed "screen" argument is NULL.

From a quick look at the code in g-s-d/plugins/power, it does this:

1. Connect to UpClient's signals in gsd_power_manager_init()

2. Initialize manager->priv->x11_screen in gsd_power_manager_start().

3. Catch a signal, process it in up_client_changed_cb()

4. Call do_lid_open_action() from there.  But at that point, screen = NULL.

Do we know if the manager has been start()ed by the time (3) happens, so that the screen is initialized?

Or did that x11_screen field get overwritten with a 0 at some point?

Comment 2 Bastien Nocera 2011-09-01 15:32:07 UTC

Created attachment 195396 [details] [review]
power: Do most of the work in _start ()

We're not supposed to start listening to signals in _init(),
but in _start(). This fixes a number of potential crashes,
including one when calling out to gnome-desktop.

Thanks for Federico Mena Quintero for the root causing.