segfault due to bug/loop in io.c or record.c

[HolySephi]

First my setup as usual:
Distribution is Ubuntu 16.04 - bash_history of compile and install:

git clone https://github.com/ArcticaProject/nx-libs.git
cd nx-libs
debuild -uc -us -j4
cd ..
dpkg -i *.deb

Using x2goserver from x2go/ppa

Right after starting a session the desktop shows for about a second and then segfaults. gdb backtrace:
https://pastebin.com/QaJGuMwX

Backtrace #6 to #10 repeat thousands of times until the last backtraces are:

#97014 0x000055a4cef83a6b in ProcRecordEnableContext (client=0x55a4d00d35a0) at record.c:2526
#97015 0x000055a4cee8c426 in Dispatch () at NXdispatch.c:482
#97016 0x000055a4cee70170 in main (argc=18, argv=0x7ffcd5ce4788, envp=) at main.c:346

Ionic stated in IRC that it might be related to the following PR:

https://github.com/ArcticaProject/nx-libs/pull/376/commits probably something in here
probably the second in here: 65b6a62

Currently it is impossible to compile nx-libs and run a x2goserver with the built packages

[Ionic]

[17:20:45] < Ionic> I'll have to compare our callbacks to upstream's at the time they wrote that commit

[uli42]

Hmm, works for me. Could not provoke this on Ubuntu 16.04

[HolySephi]

Every single time for me on different machines. I'll attach a dpkg --list tomorrow

[sunweaver]

@HolySephi: Just tested a MATE desktop with nxagent from the nightlies and no failures could be observed. You run XFCE from Ubuntu 16.04, right?

[HolySephi]

Attached is my dpkg --list with working arctica release and not working self compiled.

Yes i'm running XFCE from 16.04 repos

dpkg_selfcompiled_not_working.txt
dpkg_working.txt

[Ionic]

Note that it only happens for him when connecting via X2Go - spawning nxagent :1 manually seems to be fine.

[sunweaver]

On Mi 05 Apr 2017 10:48:37 CEST, Mihai Moldovan wrote: Note that it only happens for him when connecting via X2Go - spawning `nxagent :1` manually seems to be fine.

I tried it using X2Go, to make sure our test case is comparable. However, my connecting target host was a Debian 8 + MATE 1.8 / GTK-2. His is: Ubuntu 16.04 + XFCE (GTK-2, too). Mike -- DAS-NETZWERKTEAM mike gabriel, herweg 7, 24357 fleckeby mobile: +49 (1520) 1976 148 landline: +49 (4354) 8390 139 GnuPG Fingerprint: 9BFB AEE8 6C0A A5FF BF22 0782 9AF4 6B30 2577 1B31 mail: mike.gabriel@das-netzwerkteam.de, http://das-netzwerkteam.de

[HolySephi]

Attached is my buildlog
debuild_log.txt

[HolySephi]

bisecting the repo got me to the commit Ionic mentioned above:

65b6a62 is the first bad commit
commit 65b6a62
Author: Michel Dänzer michel.daenzer@amd.com
Date: Wed Feb 15 08:13:57 2017 +0000

dix: Pass ClientPtr to FlushCallback

.....
Backported-to-NX-by: Mike Gabriel mike.gabriel@das-netzwerkteam.de

:040000 040000 143670b2bca50b608a97a16078df502f5640cb9c f4cca236fbbd1428f47fa07b3a432efcd83024dd M nx-X11

[uli42]

Great! But why did it only happen fir Sephi? Vom Smartphone gesendet.

…

----- Ursprüngliche Nachricht ----- Von: "Mihai Moldovan" <notifications@github.com> Gesendet: ‎06.‎04.‎2017 14:14 An: "ArcticaProject/nx-libs" <nx-libs@noreply.github.com> Cc: "Ulrich Sibiller" <uli42@gmx.de>; "Comment" <comment@noreply.github.com> Betreff: Re: [ArcticaProject/nx-libs] segfault due to bug/loop in io.c orrecord.c (#417) Closed #417 via c8a4e1e. — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[HolySephi]

Just wanted to confirm the fix - segfaulting stopped with the patch from c8a4e1e