i915: intel_set_mode: Reduce stack allocation from 500 bytes to 2 pointers
smatch warning:
drivers/gpu/drm/i915/intel_display.c:7019 intel_set_mode() warn: function puts
500 bytes on stack
Refactor so that saved_mode and saved_hwmode are dynamically allocated as opposed
to being automatic variables. 500 bytes seems like it could run the potential for blowing
the kernel stack.
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 34832bc0..115bf62 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7398,11 +7398,18 @@
{
struct drm_device *dev = crtc->dev;
drm_i915_private_t *dev_priv = dev->dev_private;
- struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
+ struct drm_display_mode *adjusted_mode, *saved_mode, *saved_hwmode;
struct intel_crtc *intel_crtc;
unsigned disable_pipes, prepare_pipes, modeset_pipes;
bool ret = true;
+ saved_mode = kmalloc(2 * sizeof(*saved_mode), GFP_KERNEL);
+ if (!saved_mode) {
+ DRM_ERROR("i915: Could not allocate saved display mode.\n");
+ return false;
+ }
+ saved_hwmode = saved_mode + 1;
+
intel_modeset_affected_pipes(crtc, &modeset_pipes,
&prepare_pipes, &disable_pipes);
@@ -7412,8 +7419,8 @@
for_each_intel_crtc_masked(dev, disable_pipes, intel_crtc)
intel_crtc_disable(&intel_crtc->base);
- saved_hwmode = crtc->hwmode;
- saved_mode = crtc->mode;
+ *saved_hwmode = crtc->hwmode;
+ *saved_mode = crtc->mode;
/* Hack: Because we don't (yet) support global modeset on multiple
* crtcs, we don't keep track of the new mode for more than one crtc.
@@ -7424,7 +7431,8 @@
if (modeset_pipes) {
adjusted_mode = intel_modeset_adjusted_mode(crtc, mode);
if (IS_ERR(adjusted_mode)) {
- return false;
+ ret = false;
+ goto out;
}
}
@@ -7476,12 +7484,14 @@
done:
drm_mode_destroy(dev, adjusted_mode);
if (!ret && crtc->enabled) {
- crtc->hwmode = saved_hwmode;
- crtc->mode = saved_mode;
+ crtc->hwmode = *saved_hwmode;
+ crtc->mode = *saved_mode;
} else {
intel_modeset_check_state(dev);
}
+out:
+ kfree(saved_mode);
return ret;
}