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d2e1f939fe
During my dynamic monitor support testing today, I hit the following assert
in red_worker.c:
"red_push_monitors_config: condition `monitors_config != NULL' failed"
This is caused by the following scenario:
1) Guest causes handle_dev_monitors_config_async() to be called
2) handle_dev_monitors_config_async() calls worker_update_monitors_config()
3) handle_dev_monitors_config_async() pushes worker->monitors_config, this
takes a ref on the current monitors_config
4) Guest causes handle_dev_monitors_config_async() to be called *again*
5) handle_dev_monitors_config_async() calls worker_update_monitors_config()
6) worker_update_monitors_config() does a decref on worker->monitors_config,
releasing the workers reference, this monitor_config from step 2 is
not yet free-ed though as the pipe-item still holds a ref
7) worker_update_monitors_config() creates a new monitors_config with an
initial ref-count of 1 and stores that in worker->monitors_config
8) The pipe-item of the *first* monitors_config is send, upon completion
a decref is done on the monitors_config, and monitors_config_decref not
only frees the monitor_config, but *also* sets worker->monitors_config
to NULL, even though worker->monitors_config no longer refers to the
monitor_config being freed, it refers to the 2nd monitor_config!
9) The client which was connected when this all happened disconnects
10) A new client connects, leading to the assert:
at red_worker.c:9519
num_common_caps=1, common_caps=0x5555569b6f60, migrate=0,
stream=<optimized out>, client=<optimized out>, worker=<optimized out>)
at red_worker.c:10423
at red_worker.c:11301
Note that red_worker.c:9519 is:
red_push_monitors_config(dcc);
gdb does not point to the actual line of the assert because the function gets
inlined.
The fix is easy and obvious, don't set worker->monitors_config to NULL in
monitors_config_decref. I'm a bit baffled as to why that code is there in
the first place, the whole point of ref-counting is to not have one single
unique place to store the reference...
This fix should not have any adverse side-effects as the 4 callers of
monitors_config_decref fall into 2 categories:
1) Code which immediately after the decref replaces worker->monitors_config
with a new monitors_config:
worker_update_monitors_config()
set_monitors_config_to_primary()
2) pipe-item freeing code, which should not touch the worker state at all
to being with
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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| build-aux | ||
| client | ||
| docs | ||
| m4 | ||
| server | ||
| spice-common@b46d36bc1c | ||
| tests | ||
| tools | ||
| uncrustify_cfg | ||
| .gitignore | ||
| .gitmodules | ||
| .mailmap | ||
| AUTHORS | ||
| autogen.sh | ||
| cfg.mk | ||
| ChangeLog | ||
| configure.ac | ||
| COPYING | ||
| GITVERSION | ||
| GNUmakefile | ||
| maint.mk | ||
| Makefile.am | ||
| NEWS | ||
| README | ||
| spice-server.pc.in | ||
| TODO.multiclient | ||
SPICE: Simple Protocol for Independent Computing Environments
=============================================================
SPICE is a remote display system built for virtual environments which
allows you to view a computing 'desktop' environment not only on the
machine where it is running, but from anywhere on the Internet and
from a wide variety of machine architectures.
Installation
------------
The SPICE package uses GNU autotools, so the build install process
follows the standard process documented in the INSTALL file. As a
quick start you can do
./configure --prefix=/usr --sysconfdir=/etc \
--localstatedir=/var --libdir=/usr/lib
make
sudo make install
Or to install into a private user specific location
./configure --prefix=$HOME/spice
make
make install
The following mandatory dependancies are required in order to
build SPICE
Spice protocol >= 0.9.0
Celt >= 0.5.1.1, < 0.6.0
Pixman >= 0.17.7
OpenSSL
libjpeg
zlib
Cyrus-SASL
The following optional dependancies increase the available
functionality
GE Gui >= 0.6.0, < 0.7.0 (GUI app support)
OpenGL (GUI app support)
Alsa (Linux support)
XRandR >= 1.2 (X11 support)
Xinerama >= 1.0 (X11 support)
libcacard >= 0.1.2 (Smartcard support)
Slirp (Tunnelling support)
Communication
-------------
To communicate with the development team, or to post patches
there is a technical mailing list:
http://lists.freedesktop.org/mailman/listinfo/spice-devel
There is also a mailing list for new release announcements:
http://lists.freedesktop.org/archives/spice-announce/
To view known bugs, or report new bugs, in SPICE visit
https://bugs.freedesktop.org/describecomponents.cgi?product=Spice
Bugs found when using an OS distribution's binary packages should
be reported to the OS vendors' own bug tracker first.
The latest SPICE code can be found in GIT at:
http://cgit.freedesktop.org/spice/
Licensing
---------
SPICE is provided under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Please see the COPYING file for the complete LGPLv2+ license
terms, or visit <http://www.gnu.org/licenses/>.
Experimental Features
---------------------
To enable multiple client connections, set:
SPICE_DEBUG_ALLOW_MC=1
-- End of readme