xserver-multidpi/hw
Aaron Plattner 4226c6d032 modesetting: Check whether RandR was initialized before calling rrGetScrPriv
Calling rrGetScrPriv when RandR isn't initialized causes an assertion
failure that aborts the server:

 Xorg: ../include/privates.h:121: dixGetPrivateAddr: Assertion `key->initialized' failed.

 Thread 1 "Xorg" received signal SIGABRT, Aborted.
 0x00007ffff78a8f25 in raise () from /usr/lib/libc.so.6
 (gdb) bt
 #0  0x00007ffff78a8f25 in raise () from /usr/lib/libc.so.6
 #1  0x00007ffff7892897 in abort () from /usr/lib/libc.so.6
 #2  0x00007ffff7892767 in __assert_fail_base.cold () from /usr/lib/libc.so.6
 #3  0x00007ffff78a1526 in __assert_fail () from /usr/lib/libc.so.6
 #4  0x00007ffff7fb57c1 in dixGetPrivateAddr (privates=0x555555ab1b60, key=0x555555855720 <rrPrivKeyRec>) at ../include/privates.h:121
 #5  0x00007ffff7fb5822 in dixGetPrivate (privates=0x555555ab1b60, key=0x555555855720 <rrPrivKeyRec>) at ../include/privates.h:136
 #6  0x00007ffff7fb586a in dixLookupPrivate (privates=0x555555ab1b60, key=0x555555855720 <rrPrivKeyRec>) at ../include/privates.h:166
 #7  0x00007ffff7fb8445 in CreateScreenResources (pScreen=0x555555ab1790) at ../hw/xfree86/drivers/modesetting/driver.c:1335
 #8  0x000055555576c5e4 in xf86CrtcCreateScreenResources (screen=0x555555ab1790) at ../hw/xfree86/modes/xf86Crtc.c:744
 #9  0x00005555555d8bb6 in dix_main (argc=4, argv=0x7fffffffead8, envp=0x7fffffffeb00) at ../dix/main.c:214
 #10 0x00005555557a4f0b in main (argc=4, argv=0x7fffffffead8, envp=0x7fffffffeb00) at ../dix/stubmain.c:34

This can happen, for example, if the server is configured with Xinerama
and there is more than one X screen:

 Section "ServerLayout"
   Identifier "crash"
   Screen 0 "modesetting"
   Screen 1 "dummy" RightOf "modesetting"
   Option "Xinerama"
 EndSection

 Section "Device"
   Identifier "modesetting"
   Driver "modesetting"
 EndSection

 Section "Screen"
   Identifier "modesetting"
   Device "modesetting"
 EndSection

 Section "Device"
   Identifier "dummy"
   Driver "dummy"
 EndSection

 Section "Screen"
   Identifier "dummy"
   Device "dummy"
 EndSection

The problem does not reproduce if there is only one X screen because of
this code in xf86RandR12Init:

 #ifdef PANORAMIX
     /* XXX disable RandR when using Xinerama */
     if (!noPanoramiXExtension) {
         if (xf86NumScreens == 1)
             noPanoramiXExtension = TRUE;
         else
             return TRUE;
     }
 #endif

Fix the problem by checking dixPrivateKeyRegistered(rrPrivKey) before
calling rrGetScrPriv. This is similar to what the xf86-video-amdgpu
driver does:
fd66f5c0be/src/amdgpu_kms.c (L388)

Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
2020-01-03 08:39:21 -08:00
..
dmx dmx: Stop overriding the vendor string 2019-10-30 16:17:04 +00:00
kdrive Fix various spelling errors 2019-10-01 17:05:28 +00:00
vfb Revert https://gitlab.freedesktop.org/xorg/xserver/merge_requests/235 2019-10-14 12:48:24 +02:00
xfree86 modesetting: Check whether RandR was initialized before calling rrGetScrPriv 2020-01-03 08:39:21 -08:00
xnest mi: Add a default no-op miSourceValidate 2019-10-30 16:26:01 +00:00
xquartz include: Remove now-empty site.h 2019-10-30 16:17:04 +00:00
xwayland xwayland: Cleanup and remove xwayland.h 2019-12-20 16:19:01 +01:00
xwin XWin: Fix infinite loop in GetShift() 2019-12-12 04:54:46 +00:00
Makefile.am Xwayland DDX 2014-04-03 15:19:22 -07:00
meson.build meson: Move Xvfb build under an option. 2017-09-20 13:19:21 -04:00