Bug 105570

Summary:	[regression][bisected][crash] Crashing on startup when Composite is disabled
Product:	xorg	Reporter:	Mariusz Białończyk <manio>
Component:	Server/Ext/GLX	Assignee:	Xorg Project Team <xorg-team>
Status:	RESOLVED FIXED	QA Contact:	Xorg Project Team <xorg-team>
Severity:	major
Priority:	medium	CC:	ajax, thellstrom
Version:	git
Hardware:	Other
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Mariusz Białończyk 2018-03-17 11:57:34 UTC

Hi
Starting from version 1.19.6 the server is crashing on startup. It was working correctly on 1.19.5.
The problem occurs only when composite extension is disabled (Option "Composite" "Disable") in xorg.conf.

I bisected the bad commits. There are two of them, which has to be reverted (tested with every single one reverted and it was crashing - so I had to revert both of them). The problematic commits are:

91c42093b248 glx: Duplicate relevant fbconfigs for compositing visuals
c64bd21d7a73 glx: Move Composite's synthetic visuals to a different select group

The backtrace:
[513365.394] (EE) Backtrace:
[513365.394] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4a) [0x56062ea8c2ea]
[513365.394] (EE) 1: /usr/lib/xorg/Xorg (0x56062e8d3000+0x1bd079) [0x56062ea90079]
[513365.394] (EE) 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7ff6bd2fc000+0x12180) [0x7ff6bd30e180]
[513365.394] (EE) 3: /lib/x86_64-linux-gnu/libc.so.6 (gsignal+0x110) [0x7ff6bcf7a6a0]
[513365.394] (EE) 4: /lib/x86_64-linux-gnu/libc.so.6 (abort+0x1c7) [0x7ff6bcf7bcf7]
[513365.394] (EE) 5: /lib/x86_64-linux-gnu/libc.so.6 (0x7ff6bcf46000+0x2cfca) [0x7ff6bcf72fca]
[513365.394] (EE) 6: /lib/x86_64-linux-gnu/libc.so.6 (0x7ff6bcf46000+0x2d042) [0x7ff6bcf73042]
[513365.394] (EE) 7: /usr/lib/xorg/Xorg (0x56062e8d3000+0x3ed60) [0x56062e911d60]
[513365.394] (EE) 8: /usr/lib/xorg/Xorg (0x56062e8d3000+0xe3ffd) [0x56062e9b6ffd]
[513365.394] (EE) 9: /usr/lib/xorg/modules/extensions/libglx.so (0x7ff6bb301000+0x28a39) [0x7ff6bb329a39]
[513365.394] (EE) 10: /usr/lib/xorg/modules/extensions/libglx.so (0x7ff6bb301000+0x2fac4) [0x7ff6bb330ac4]
[513365.394] (EE) 11: /usr/lib/xorg/modules/extensions/libglx.so (0x7ff6bb301000+0x274aa) [0x7ff6bb3284aa]
[513365.394] (EE) 12: /usr/lib/xorg/Xorg (InitExtensions+0x43) [0x56062e99a8f3]
[513365.394] (EE) 13: /usr/lib/xorg/Xorg (0x56062e8d3000+0x585f7) [0x56062e92b5f7]
[513365.394] (EE) 14: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xea) [0x7ff6bcf66f2a]
[513365.394] (EE) 15: /usr/lib/xorg/Xorg (_start+0x2a) [0x56062e91546a]
[513365.394] (EE)
[513365.394] (EE)
Fatal server error:
[513365.394] (EE) Caught signal 6 (Aborted). Server aborting
[513365.394] (EE)
[513365.394] (EE)

Firstly I reported the bug on debian:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=891287
There you can find additional platform info if necessary.

regards!

Comment 1 Ed Martin 2018-04-25 18:44:53 UTC

I think this is a dup of bug 106226 considering that the problem check-in seems to be the same.

Comment 2 Adam Jackson 2018-06-12 17:25:56 UTC

Why do you think disabling Composite is a thing you need to do?

Comment 3 Mariusz Białończyk 2018-06-12 18:59:16 UTC

Adam,
Yeah, composite may be working perfectly fine but on standard configurations, in my case I always have performance problems/flickering/segfaults* when it is enabled. The "problem" here is I am simultaneously using four monitors on two different adapters (and xinerama is a must here) :)

* Depending on xorg version and specific time when I was trying to enable it again :)

btw: some day I'd like to use wayland but I am still waiting for multi gpu support...

Comment 4 Michel Dänzer 2018-06-13 09:39:48 UTC

(In reply to Mariusz Białończyk from comment #3)
> btw: some day I'd like to use wayland but I am still waiting for multi gpu
> support...

Current versions of gnome-shell support multiple GPUs in Wayland mode.

Comment 5 Mariusz Białończyk 2018-07-09 20:35:36 UTC

I am confirming that this bug is now fixed with Michal Srb's commit:
1326ee0bc5eb858c3c00847: glx: Do not call into Composite if it is disabled.

I've marked it as fixed. Thank you!

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.