drm: Don't call drm_for_each_crtc with a non-KMS driver
Fixes oops if userspace calls DRM_IOCTL_GET_CAP for
DRM_CAP_PAGE_FLIP_TARGET on a non-KMS device node. (Normal userspace
doesn't do that, discovered by syzkaller)
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: f837297ad8
("drm: Add DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE/RELATIVE flags v2")
Cc: stable@vger.kernel.org
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161130083002.1520-1-michel@daenzer.net
This commit is contained in:

committed by
Daniel Vetter

parent
e5517c2a5a
commit
e94bd1736f
@@ -254,10 +254,12 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
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req->value = dev->mode_config.async_page_flip;
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req->value = dev->mode_config.async_page_flip;
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break;
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break;
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case DRM_CAP_PAGE_FLIP_TARGET:
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case DRM_CAP_PAGE_FLIP_TARGET:
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req->value = 1;
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if (drm_core_check_feature(dev, DRIVER_MODESET)) {
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drm_for_each_crtc(crtc, dev) {
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req->value = 1;
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if (!crtc->funcs->page_flip_target)
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drm_for_each_crtc(crtc, dev) {
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req->value = 0;
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if (!crtc->funcs->page_flip_target)
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req->value = 0;
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}
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}
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}
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break;
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break;
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case DRM_CAP_CURSOR_WIDTH:
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case DRM_CAP_CURSOR_WIDTH:
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