* [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes
@ 2022-07-26 15:20 Dan Carpenter
2022-07-26 15:27 ` Simon Ser
0 siblings, 1 reply; 7+ messages in thread
From: Dan Carpenter @ 2022-07-26 15:20 UTC (permalink / raw)
To: contact; +Cc: amd-gfx
Hello Simon Ser,
The patch 03a663673063: "drm/amd/display: use FB pitch to fill
dc_cursor_attributes" from Dec 2, 2020, leads to the following Smatch
static checker warning:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:1271 handle_cursor_update()
error: we previously assumed 'afb' could be null (see line 1230)
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c
1222 void handle_cursor_update(struct drm_plane *plane,
1223 struct drm_plane_state *old_plane_state)
1224 {
1225 struct amdgpu_device *adev = drm_to_adev(plane->dev);
1226 struct amdgpu_framebuffer *afb = to_amdgpu_framebuffer(plane->state->fb);
1227 struct drm_crtc *crtc = afb ? plane->state->crtc : old_plane_state->crtc;
afb is container_of() but it's basically a cast in this case. I would
always prefer to check "plane->state->fb" for NULL instead of the
container_of(), but that's sort of a style debate, I guess. Some people
really like checking the returned pointer and add build time asserts to
ensure that the container_of() is a no-op.
1228 struct dm_crtc_state *crtc_state = crtc ? to_dm_crtc_state(crtc->state) : NULL;
1229 struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
1230 uint64_t address = afb ? afb->address : 0;
1231 struct dc_cursor_position position = {0};
1232 struct dc_cursor_attributes attributes;
1233 int ret;
1234
1235 if (!plane->state->fb && !old_plane_state->fb)
1236 return;
1237
1238 DC_LOG_CURSOR("%s: crtc_id=%d with size %d to %d\n",
1239 __func__,
1240 amdgpu_crtc->crtc_id,
1241 plane->state->crtc_w,
1242 plane->state->crtc_h);
1243
1244 ret = get_cursor_position(plane, crtc, &position);
1245 if (ret)
1246 return;
1247
1248 if (!position.enable) {
1249 /* turn off cursor */
1250 if (crtc_state && crtc_state->stream) {
1251 mutex_lock(&adev->dm.dc_lock);
1252 dc_stream_set_cursor_position(crtc_state->stream,
1253 &position);
1254 mutex_unlock(&adev->dm.dc_lock);
1255 }
1256 return;
1257 }
1258
1259 amdgpu_crtc->cursor_width = plane->state->crtc_w;
1260 amdgpu_crtc->cursor_height = plane->state->crtc_h;
1261
1262 memset(&attributes, 0, sizeof(attributes));
1263 attributes.address.high_part = upper_32_bits(address);
1264 attributes.address.low_part = lower_32_bits(address);
1265 attributes.width = plane->state->crtc_w;
1266 attributes.height = plane->state->crtc_h;
1267 attributes.color_format = CURSOR_MODE_COLOR_PRE_MULTIPLIED_ALPHA;
1268 attributes.rotation_angle = 0;
1269 attributes.attribute_flags.value = 0;
1270
--> 1271 attributes.pitch = afb->base.pitches[0] / afb->base.format->cpp[0];
^^^^^ ^^^^^
Unchecked dereferences.
1272
1273 if (crtc_state->stream) {
1274 mutex_lock(&adev->dm.dc_lock);
1275 if (!dc_stream_set_cursor_attributes(crtc_state->stream,
1276 &attributes))
1277 DRM_ERROR("DC failed to set cursor attributes\n");
1278
1279 if (!dc_stream_set_cursor_position(crtc_state->stream,
1280 &position))
1281 DRM_ERROR("DC failed to set cursor position\n");
1282 mutex_unlock(&adev->dm.dc_lock);
1283 }
1284 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes
2022-07-26 15:20 [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes Dan Carpenter
@ 2022-07-26 15:27 ` Simon Ser
2022-07-26 15:47 ` Dan Carpenter
0 siblings, 1 reply; 7+ messages in thread
From: Simon Ser @ 2022-07-26 15:27 UTC (permalink / raw)
To: Dan Carpenter; +Cc: amd-gfx
Hi,
plane->state->fb is NULL iff afb is NULL. There is an early return to
make sure the dereferences don't cause a segfault.
Simon
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes
2022-07-26 15:27 ` Simon Ser
@ 2022-07-26 15:47 ` Dan Carpenter
2022-07-26 17:16 ` Simon Ser
0 siblings, 1 reply; 7+ messages in thread
From: Dan Carpenter @ 2022-07-26 15:47 UTC (permalink / raw)
To: Simon Ser; +Cc: amd-gfx
On Tue, Jul 26, 2022 at 03:27:54PM +0000, Simon Ser wrote:
> Hi,
>
> plane->state->fb is NULL iff afb is NULL. There is an early return to
> make sure the dereferences don't cause a segfault.
>
Are you talking about this:
if (!plane->state->fb && !old_plane_state->fb)
return;
Should the && be ||?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes
2022-07-26 15:47 ` Dan Carpenter
@ 2022-07-26 17:16 ` Simon Ser
0 siblings, 0 replies; 7+ messages in thread
From: Simon Ser @ 2022-07-26 17:16 UTC (permalink / raw)
To: Dan Carpenter; +Cc: amd-gfx
On Tuesday, July 26th, 2022 at 17:47, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> On Tue, Jul 26, 2022 at 03:27:54PM +0000, Simon Ser wrote:
>
> > plane->state->fb is NULL iff afb is NULL. There is an early return to
> > make sure the dereferences don't cause a segfault.
>
>
> Are you talking about this:
>
> if (!plane->state->fb && !old_plane_state->fb)
>
> return;
>
> Should the && be ||?
Ah, sorry, the reason why this doesn't segfault is different:
get_cursor_position() will leave position.enable = false if there is no
FB, and we have an early return for that. This also guards crtc_state.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes
2020-12-07 14:53 ` Simon Ser
@ 2020-12-07 17:51 ` Dan Carpenter
0 siblings, 0 replies; 7+ messages in thread
From: Dan Carpenter @ 2020-12-07 17:51 UTC (permalink / raw)
To: Simon Ser; +Cc: amd-gfx
On Mon, Dec 07, 2020 at 02:53:28PM +0000, Simon Ser wrote:
> Hi,
>
> On Monday, December 7th, 2020 at 3:51 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> > The patch adds some new unchecked dereferences.
>
> The `if (!position.enable)` check above should ensure the dereference
> isn't unchecked.
Yeah. You're correct. Thanks, for looking into this.
regards,
dan carpenter
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes
2020-12-07 14:51 Dan Carpenter
@ 2020-12-07 14:53 ` Simon Ser
2020-12-07 17:51 ` Dan Carpenter
0 siblings, 1 reply; 7+ messages in thread
From: Simon Ser @ 2020-12-07 14:53 UTC (permalink / raw)
To: Dan Carpenter; +Cc: amd-gfx
Hi,
On Monday, December 7th, 2020 at 3:51 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> The patch adds some new unchecked dereferences.
The `if (!position.enable)` check above should ensure the dereference
isn't unchecked.
Simon
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
^ permalink raw reply [flat|nested] 7+ messages in thread
* [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes
@ 2020-12-07 14:51 Dan Carpenter
2020-12-07 14:53 ` Simon Ser
0 siblings, 1 reply; 7+ messages in thread
From: Dan Carpenter @ 2020-12-07 14:51 UTC (permalink / raw)
To: contact; +Cc: amd-gfx
Hello Simon Ser,
This is a semi-automatic email about new static checker warnings.
The patch 03a663673063: "drm/amd/display: use FB pitch to fill
dc_cursor_attributes" from Dec 2, 2020, leads to the following Smatch
complaint:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:7438 handle_cursor_update()
error: we previously assumed 'afb' could be null (see line 7397)
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c
7389 static void handle_cursor_update(struct drm_plane *plane,
7390 struct drm_plane_state *old_plane_state)
7391 {
7392 struct amdgpu_device *adev = drm_to_adev(plane->dev);
7393 struct amdgpu_framebuffer *afb = to_amdgpu_framebuffer(plane->state->fb);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If "plane->state->fb" is NULL then "afb" is NULL.
7394 struct drm_crtc *crtc = afb ? plane->state->crtc : old_plane_state->crtc;
^^^
Checked for NULL.
7395 struct dm_crtc_state *crtc_state = crtc ? to_dm_crtc_state(crtc->state) : NULL;
7396 struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
7397 uint64_t address = afb ? afb->address : 0;
7398 struct dc_cursor_position position;
7399 struct dc_cursor_attributes attributes;
7400 int ret;
7401
7402 if (!plane->state->fb && !old_plane_state->fb)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
These aren't allow to be both NULL
7403 return;
7404
7405 DRM_DEBUG_DRIVER("%s: crtc_id=%d with size %d to %d\n",
7406 __func__,
7407 amdgpu_crtc->crtc_id,
7408 plane->state->crtc_w,
7409 plane->state->crtc_h);
7410
7411 ret = get_cursor_position(plane, crtc, &position);
7412 if (ret)
7413 return;
7414
7415 if (!position.enable) {
7416 /* turn off cursor */
7417 if (crtc_state && crtc_state->stream) {
7418 mutex_lock(&adev->dm.dc_lock);
7419 dc_stream_set_cursor_position(crtc_state->stream,
7420 &position);
7421 mutex_unlock(&adev->dm.dc_lock);
7422 }
7423 return;
7424 }
7425
7426 amdgpu_crtc->cursor_width = plane->state->crtc_w;
7427 amdgpu_crtc->cursor_height = plane->state->crtc_h;
7428
7429 memset(&attributes, 0, sizeof(attributes));
7430 attributes.address.high_part = upper_32_bits(address);
7431 attributes.address.low_part = lower_32_bits(address);
7432 attributes.width = plane->state->crtc_w;
7433 attributes.height = plane->state->crtc_h;
7434 attributes.color_format = CURSOR_MODE_COLOR_PRE_MULTIPLIED_ALPHA;
7435 attributes.rotation_angle = 0;
7436 attributes.attribute_flags.value = 0;
7437
7438 attributes.pitch = afb->base.pitches[0] / afb->base.format->cpp[0];
^^^^^ ^^^^^
The patch adds some new unchecked dereferences.
7439
7440 if (crtc_state->stream) {
regards,
dan carpenter
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-07-26 17:16 UTC | newest]
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2022-07-26 15:20 [bug report] drm/amd/display: use FB pitch to fill dc_cursor_attributes Dan Carpenter
2022-07-26 15:27 ` Simon Ser
2022-07-26 15:47 ` Dan Carpenter
2022-07-26 17:16 ` Simon Ser
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2020-12-07 14:51 Dan Carpenter
2020-12-07 14:53 ` Simon Ser
2020-12-07 17:51 ` Dan Carpenter
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