Bug 77503

Summary:	Weston crashes (Segmentation fault) immediately on specifying seat
Product:	Wayland	Reporter:	Anu Reddy <anasuyax.r.nannuri>
Component:	weston	Assignee:	Wayland bug list <wayland-bugs>
Status:	VERIFIED FIXED	QA Contact:
Severity:	critical
Priority:	medium
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	bad-seat-gdb-backtrace.out

Description Anu Reddy 2014-04-15 21:52:15 UTC

Weston crashes on specifying seat for output in weston.ini. Weston received signal SIGSEGV, Segmentation fault. I am able to reproduce this every time. See attached gdb_backtrace.  

Steps:
1. Configure Weston.ini with seat=back0

Example:
Output
name=HDMI2
seat=back0

2. Launch Weston
3. Notice, weston crashes immediately with segmentation fault.


Software stack:
wayland (HEAD) 1.4.91-0-g5e2cfd2
drm (HEAD) libdrm-2.4.52-0-g46d451c
mesa (HEAD) mesa-10.1-0-g4a86465
libva (HEAD) libva-1.2.1-0-g88ed1eb
intel-driver (HEAD) 1.2.2-0-g121e70d
cairo (HEAD) heads/1.12-0-g59e2a93
libinput (HEAD) remotes/origin/HEAD-0-gc5c503c
weston (HEAD) 1.4.91-0-g79d5a6e

Comment 1 Anu Reddy 2014-04-15 21:54:38 UTC

Created attachment 97428 [details]
bad-seat-gdb-backtrace.out

Comment 2 Ander Conselvan de Oliveira 2014-04-16 12:54:01 UTC

This one seems to be cause by an API change done for introducing libinput support. Commit 58e15865 changed the parameters for udev_get_seat_by_name() to receive a struct udev_input. However, when this gets called from create_output_for_connector() during initialization, we haven't initialized that udev_input structure, leading to the crash.

Comment 3 Kristian Høgsberg 2014-04-21 20:05:04 UTC

commit 6f4c63740bd6d360f74568501d3748adeb0e5e29
Author: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Date:   Thu Apr 17 13:08:45 2014 +0300

    compositor-drm: Fix crash when setting up seat constrained by an output
    
    Commit 58e15865 changed the parameters for udev_get_seat_by_name() to
    receive a struct udev_input. However, when this gets called from
    create_output_from_connector() during initialization, the input struct
    is not yet initialized, leading to a crash. Previously, that function
    would take only a pointer to the compositor.
    
    This patch fixes the crash by initializing input before creating any
    outputs.
    
    https://bugs.freedesktop.org/show_bug.cgi?id=77503

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