From: Tim Gardner Date: Fri, 7 Dec 2012 14:54:26 +0000 (-0700) Subject: i915: intel_set_mode: Reduce stack allocation from 500 bytes to 2 pointers X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3ac18232946aacf0a9807c3143f8449ed4aa68f4;p=linux-beck.git 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 Cc: David Airlie Cc: dri-devel@lists.freedesktop.org Signed-off-by: Tim Gardner Reviewed-by: Jani Nikula Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 34832bc04931..115bf626037c 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7398,11 +7398,18 @@ 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) { + 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 @@ 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. @@ -7424,7 +7431,8 @@ bool intel_set_mode(struct drm_crtc *crtc, 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 @@ 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); } +out: + kfree(saved_mode); return ret; }