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: https://github.com/ArcticaProject/nx-libs/pull/376/commits/65b6a62bc726b5e4f4833ed1e27733e22fabcfa8

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

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[HolySephi]

Attached is my buildlog debuild_log.txt

[HolySephi]

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

65b6a62bc726b5e4f4833ed1e27733e22fabcfa8 is the first bad commit commit 65b6a62bc726b5e4f4833ed1e27733e22fabcfa8 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 https://github.com/ArcticaProject/nx-libs/commit/c8a4e1e75c745c5c3ad947ba61c52cc5963d31dd