From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [Intel-gfx] [bug report] drm/i915: Fix enabled_planes bitmask
Date: Wed, 24 Mar 2021 15:31:20 +0200 [thread overview]
Message-ID: <YFs/KA78gK3eGEu1@intel.com> (raw)
In-Reply-To: <YFrozlRheXy9ziyK@mwanda>
On Wed, Mar 24, 2021 at 10:22:54AM +0300, Dan Carpenter wrote:
> Hello Ville Syrjälä,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch 97bc7ffa1b1e: "drm/i915: Fix enabled_planes bitmask" from
> Mar 5, 2021, leads to the following Smatch complaint:
>
> drivers/gpu/drm/i915/display/intel_atomic_plane.c:332 intel_plane_atomic_check_with_state()
> error: we previously assumed 'fb' could be null (see line 324)
>
> drivers/gpu/drm/i915/display/intel_atomic_plane.c
> 323
> 324 if (fb)
> ^^
> The patch adds a check for NULL
>
> 325 new_crtc_state->enabled_planes |= BIT(plane->id);
> 326
> 327 /* FIXME pre-g4x don't work like this */
> 328 if (new_plane_state->uapi.visible)
> 329 new_crtc_state->active_planes |= BIT(plane->id);
> 330
> 331 if (new_plane_state->uapi.visible &&
> 332 intel_format_info_is_yuv_semiplanar(fb->format, fb->modifier))
> ^^^^^^^^^^^^^^^^^^^^^^^^
> Unchecked deref
>
> 333 new_crtc_state->nv12_planes |= BIT(plane->id);
> 334
> 335 if (new_plane_state->uapi.visible &&
> 336 fb->format->format == DRM_FORMAT_C8)
> ^^^^^^^^^^
> Same. These are potentially false positives. I don't know if
> "uapi.visible" can be true when ctrc is non-NULL and fb is NULL for
> example? (The point is I read the commit message, but I know pants all
> about DRM. :P)
If there's no fb then uapi.visible=false. See
intel_atomic_plane_check_clipping().
>
> 337 new_crtc_state->c8_planes |= BIT(plane->id);
> 338
> 339 if (new_plane_state->uapi.visible || old_plane_state->uapi.visible)
> 340 new_crtc_state->update_planes |= BIT(plane->id);
> 341
> 342 new_crtc_state->data_rate[plane->id] =
> 343 intel_plane_data_rate(new_crtc_state, new_plane_state);
> 344
> 345 return intel_plane_atomic_calc_changes(old_crtc_state, new_crtc_state,
> 346 old_plane_state, new_plane_state);
> 347 }
>
> regards,
> dan carpenter
--
Ville Syrjälä
Intel
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prev parent reply other threads:[~2021-03-24 13:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 7:22 [Intel-gfx] [bug report] drm/i915: Fix enabled_planes bitmask Dan Carpenter
2021-03-24 13:31 ` Ville Syrjälä [this message]
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