| Message ID | 1354815755-83271-1-git-send-email-tim.gardner@canonical.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
On Fri, 07 Dec 2012 13:47:46 +0200, Jani Nikula <jani.nikula@linux.intel.com> wrote: > > On Thu, 06 Dec 2012, Tim Gardner <tim.gardner@canonical.com> wrote: > > + if (!saved_mode) { > > + pr_err("i915: Could not allocate saved display mode.\n"); > > Please use DRM_ERROR(). Truthfully neither, but join the growing petition to get real errorcodes back to userspace! -Chris
On Fri, 07 Dec 2012, Chris Wilson <chris@chris-wilson.co.uk> wrote: > On Fri, 07 Dec 2012 13:47:46 +0200, Jani Nikula <jani.nikula@linux.intel.com> wrote: >> >> On Thu, 06 Dec 2012, Tim Gardner <tim.gardner@canonical.com> wrote: >> > + if (!saved_mode) { >> > + pr_err("i915: Could not allocate saved display mode.\n"); >> >> Please use DRM_ERROR(). > > Truthfully neither, but join the growing petition to get real errorcodes > back to userspace! Heh, agreed, but in the mean time (i.e. before hell freezes over) I think we should prefer DRM_ERROR over pr_err for consistency. Jani.
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; }
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(-)