Xwayland creates and destroys the CRTC along with the Wayland outputs,
so there is possibly a case where the number of CRTC drops to 0.
However, `xwl_present_get_crtc()` always return `crtcs[0]` which is
invalid when `numCrtcs` is 0.
That leads to crash if a client queries the Present capabilities when
there is no CRTC, the backtrace looks like:
#0 raise() from libc.so
#1 abort() from libc.so
#2 OsAbort() at utils.c:1350
#3 AbortServer() at log.c:879
#4 FatalError() at log.c:1017
#5 OsSigHandler() at osinit.c:156
#6 OsSigHandler() at osinit.c:110
#7 <signal handler called>
#8 main_arena() from libc.so
#9 proc_present_query_capabilities() at present_request.c:236
#10 Dispatch() at dispatch.c:478
#11 dix_main() at main.c:276
To avoid returning an invalid pointer (`crtcs[0]`) in that case, simply
check for `numCrtcs` being 0 and return `NULL` in that case.
Thanks to Michel Dänzer <michel.daenzer@amd.com> for pointing this as a
possible cause of the crash.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Bugzilla: https://bugzilla.redhat.com/1609181
(cherry picked from commit
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composite | ||
config | ||
damageext | ||
dbe | ||
dix | ||
doc | ||
dri3 | ||
exa | ||
fb | ||
glamor | ||
glx | ||
hw | ||
include | ||
m4 | ||
man | ||
mi | ||
miext | ||
os | ||
present | ||
pseudoramiX | ||
randr | ||
record | ||
render | ||
test | ||
Xext | ||
xfixes | ||
Xi | ||
xkb | ||
.appveyor.yml | ||
.dir-locals.el | ||
.gitignore | ||
.gitlab-ci.yml | ||
.travis.yml | ||
autogen.sh | ||
configure.ac | ||
COPYING | ||
devbook.am | ||
docbook.am | ||
fix-miregion | ||
fix-miregion-private | ||
fix-patch-whitespace | ||
fix-region | ||
Makefile.am | ||
manpages.am | ||
meson_options.txt | ||
meson.build | ||
README | ||
xorg-server.m4 | ||
xorg-server.pc.in | ||
xserver.ent.in |
X Server The X server accepts requests from client applications to create windows, which are (normally rectangular) "virtual screens" that the client program can draw into. Windows are then composed on the actual screen by the X server (or by a separate composite manager) as directed by the window manager, which usually communicates with the user via graphical controls such as buttons and draggable titlebars and borders. For a comprehensive overview of X Server and X Window System, consult the following article: https://en.wikipedia.org/wiki/X_server All questions regarding this software should be directed at the Xorg mailing list: https://lists.freedesktop.org/mailman/listinfo/xorg Please submit bug reports to the Xorg bugzilla: https://bugs.freedesktop.org/enter_bug.cgi?product=xorg The master development code repository can be found at: git://anongit.freedesktop.org/git/xorg/xserver https://cgit.freedesktop.org/xorg/xserver For patch submission instructions, see: https://www.x.org/wiki/Development/Documentation/SubmittingPatches For more information on the git code manager, see: https://wiki.x.org/wiki/GitPage As with other projects hosted on freedesktop.org, X.Org follows its Code of Conduct, based on the Contributor Covenant. Please conduct yourself in a respectful and civilized manner when using the above mailing lists, bug trackers, etc: https://www.freedesktop.org/wiki/CodeOfConduct