Commit 4226c6d0 authored by Aaron Plattner's avatar Aaron Plattner

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:
https://gitlab.freedesktop.org/xorg/driver/xf86-video-amdgpu/blob/fd66f5c0bea2b7c22a47bfd5eb1f22d32d166d9c/src/amdgpu_kms.c#L388Signed-off-by: Aaron Plattner's avatarAaron Plattner <aplattner@nvidia.com>
Reviewed-by: Michel Dänzer's avatarMichel Dänzer <mdaenzer@redhat.com>
parent b1ee4036
Pipeline #93618 passed with stages
in 4 minutes and 7 seconds
......@@ -1368,7 +1368,6 @@ static Bool
CreateScreenResources(ScreenPtr pScreen)
{
ScrnInfoPtr pScrn = xf86ScreenToScrn(pScreen);
rrScrPrivPtr pScrPriv = rrGetScrPriv(pScreen);
modesettingPtr ms = modesettingPTR(pScrn);
PixmapPtr rootPixmap;
Bool ret;
......@@ -1434,10 +1433,14 @@ CreateScreenResources(ScreenPtr pScreen)
}
}
pScrPriv->rrEnableSharedPixmapFlipping = msEnableSharedPixmapFlipping;
pScrPriv->rrDisableSharedPixmapFlipping = msDisableSharedPixmapFlipping;
if (dixPrivateKeyRegistered(rrPrivKey)) {
rrScrPrivPtr pScrPriv = rrGetScrPriv(pScreen);
pScrPriv->rrStartFlippingPixmapTracking = msStartFlippingPixmapTracking;
pScrPriv->rrEnableSharedPixmapFlipping = msEnableSharedPixmapFlipping;
pScrPriv->rrDisableSharedPixmapFlipping = msDisableSharedPixmapFlipping;
pScrPriv->rrStartFlippingPixmapTracking = msStartFlippingPixmapTracking;
}
return ret;
}
......
......@@ -3245,13 +3245,19 @@ static void
drmmode_validate_leases(ScrnInfoPtr scrn)
{
ScreenPtr screen = scrn->pScreen;
rrScrPrivPtr scr_priv = rrGetScrPriv(screen);
rrScrPrivPtr scr_priv;
modesettingPtr ms = modesettingPTR(scrn);
drmmode_ptr drmmode = &ms->drmmode;
drmModeLesseeListPtr lessees;
RRLeasePtr lease, next;
int l;
/* Bail out if RandR wasn't initialized. */
if (!dixPrivateKeyRegistered(rrPrivKey))
return;
scr_priv = rrGetScrPriv(screen);
/* We can't talk to the kernel about leases when VT switched */
if (!scrn->vtSema)
return;
......
......@@ -220,7 +220,7 @@ static RRCrtcPtr
ms_covering_randr_crtc(ScreenPtr pScreen, BoxPtr box, Bool screen_is_ms)
{
ScrnInfoPtr scrn = xf86ScreenToScrn(pScreen);
rrScrPrivPtr pScrPriv = rrGetScrPriv(pScreen);
rrScrPrivPtr pScrPriv;
RRCrtcPtr crtc, best_crtc;
int coverage, best_coverage;
int c;
......@@ -230,6 +230,11 @@ ms_covering_randr_crtc(ScreenPtr pScreen, BoxPtr box, Bool screen_is_ms)
best_crtc = NULL;
best_coverage = 0;
if (!dixPrivateKeyRegistered(rrPrivKey))
return NULL;
pScrPriv = rrGetScrPriv(pScreen);
if (!pScrPriv)
return NULL;
......
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