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.
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); + if (!saved_mode) { + pr_err("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);
@@ -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. @@ -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; }