On Thu, 06 Dec 2012, Tim Gardner tim.gardner@canonical.com wrote:
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, especially if struct drm_display_mode ever grows significantly.
Hi Tim, seems reasonable, but please find a few comments inline.
BR, Jani.
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
drivers/gpu/drm/i915/intel_display.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index de51489..f8754d6 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7739,11 +7739,18 @@ bool intel_set_mode(struct drm_crtc *crtc, { 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);
Style nitpick, missing spaces around the first *.
- if (!saved_mode) {
pr_err("i915: Could not allocate saved display mode.\n");
Please use DRM_ERROR().
return false;- }
- saved_hwmode = saved_mode + 1;
- intel_modeset_affected_pipes(crtc, &modeset_pipes, &prepare_pipes, &disable_pipes);
@@ -7753,8 +7760,8 @@ bool intel_set_mode(struct drm_crtc *crtc, 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.
You are missing a kfree in the adjusted_mode error path after this hunk.
@@ -7817,12 +7824,13 @@ bool intel_set_mode(struct drm_crtc *crtc, 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); }
kfree(saved_mode); return ret;
}
-- 1.7.9.5
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