diff options
author | Alex Goins <agoins@nvidia.com> | 2019-08-28 18:24:16 -0500 |
---|---|---|
committer | Aaron Plattner <aplattner@nvidia.com> | 2019-11-11 14:35:57 -0800 |
commit | 3ef9029ace4245d9f8929aa71e22bc6a6f40b7b3 (patch) | |
tree | 0609f6c1f183861a7f5fd04e4af8e9803964aff8 | |
parent | c82f814313a813d7e1a2d7d3b1f7561810446b34 (diff) |
modesetting: Fix ms_covering_crtc() segfault with non-modesetting slave primary
ms_covering_crtc() uses RRFirstOutput() to determine a primary output to fall
back to if a drawable is overlapping a slave output.
If the primary output is a slave output, RRFirstOutput() will return a slave
output even if passed a master ScreenPtr. ms_covering_crtc() dereferences the
output's devPrivate, which is invalid for non-modesetting outputs, and can
crash.
Changing RRFirstOutput() could have unintended side effects for other callers,
so this change replaces the call to RRFirstOutput() with ms_first_output().
ms_first_output() ignores the primary output if it doesn't match the given
ScreenPtr, choosing the first connected output instead.
Signed-off-by: Alex Goins <agoins@nvidia.com>
-rw-r--r-- | hw/xfree86/drivers/modesetting/vblank.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/hw/xfree86/drivers/modesetting/vblank.c b/hw/xfree86/drivers/modesetting/vblank.c index d5799d526..b38e5d4ec 100644 --- a/hw/xfree86/drivers/modesetting/vblank.c +++ b/hw/xfree86/drivers/modesetting/vblank.c @@ -91,6 +91,39 @@ ms_crtc_on(xf86CrtcPtr crtc) } /* + * Return the first output which is connected to an active CRTC on this screen. + * + * RRFirstOutput() will return an output from a slave screen if it is primary, + * which is not the behavior that ms_covering_crtc() wants. + */ + +static RROutputPtr ms_first_output(ScreenPtr pScreen) +{ + rrScrPriv(pScreen); + RROutputPtr output; + int i, j; + + if (!pScrPriv) + return NULL; + + if (pScrPriv->primaryOutput && pScrPriv->primaryOutput->crtc && + (pScrPriv->primaryOutput->pScreen == pScreen)) { + return pScrPriv->primaryOutput; + } + + for (i = 0; i < pScrPriv->numCrtcs; i++) { + RRCrtcPtr crtc = pScrPriv->crtcs[i]; + + for (j = 0; j < pScrPriv->numOutputs; j++) { + output = pScrPriv->outputs[j]; + if (output->crtc == crtc) + return output; + } + } + return NULL; +} + +/* * Return the crtc covering 'box'. If two crtcs cover a portion of * 'box', then prefer the crtc with greater coverage. */ @@ -135,7 +168,7 @@ ms_covering_crtc(ScreenPtr pScreen, BoxPtr box, Bool screen_is_ms) ScreenPtr slave; if (dixPrivateKeyRegistered(rrPrivKey)) - primary_output = RRFirstOutput(scrn->pScreen); + primary_output = ms_first_output(scrn->pScreen); if (!primary_output || !primary_output->crtc) return NULL; |