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authorMichel Dänzer <michel.daenzer@amd.com>2016-11-30 17:30:01 +0900
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-11-30 10:13:00 +0100
commite94bd1736f1f60e916a85a80c0b0ebeaae36cce5 (patch)
tree6be5bed68a1db424105a5f5f4513129b4c376f07
parente5517c2a5a49ed5e99047008629f1cd60246ea0e (diff)
drm: Don't call drm_for_each_crtc with a non-KMS driverdrm-misc-fixes-2016-11-30
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: f837297ad824 ("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
-rw-r--r--drivers/gpu/drm/drm_ioctl.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 0ad2c47f808f..71c3473476c7 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -254,10 +254,12 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
req->value = dev->mode_config.async_page_flip;
break;
case DRM_CAP_PAGE_FLIP_TARGET:
- req->value = 1;
- drm_for_each_crtc(crtc, dev) {
- if (!crtc->funcs->page_flip_target)
- req->value = 0;
+ if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+ req->value = 1;
+ drm_for_each_crtc(crtc, dev) {
+ if (!crtc->funcs->page_flip_target)
+ req->value = 0;
+ }
}
break;
case DRM_CAP_CURSOR_WIDTH:

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