This is a note to let you know that I've just added the patch titled
drm/stm: ltdc: fix late dereference check
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-stm-ltdc-fix-late-dereference-check.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 54a4bda96e94823c86ff9366a41aceb1a2ed9f40
Author: Raphael Gallais-Pou <raphael.gallais-pou@xxxxxxxxxxx>
Date: Mon May 15 14:38:18 2023 +0200
drm/stm: ltdc: fix late dereference check
[ Upstream commit 898a9e3f56db9860ab091d4bf41b6caa99aafc3d ]
In ltdc_crtc_set_crc_source(), struct drm_crtc was dereferenced in a
container_of() before the pointer check. This could cause a kernel panic.
Fix this smatch warning:
drivers/gpu/drm/stm/ltdc.c:1124 ltdc_crtc_set_crc_source() warn: variable dereferenced before check 'crtc' (see line 1119)
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/lkml/202212241802.zeLFZCXB-lkp@xxxxxxxxx/
Reported-by: Dan Carpenter <error27@xxxxxxxxx>
Closes: https://lore.kernel.org/lkml/202212241802.zeLFZCXB-lkp@xxxxxxxxx/
Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@xxxxxxxxxxx>
Acked-by: Philippe Cornu <philippe.cornu@xxxxxxxxxxx>
Signed-off-by: Philippe Cornu <philippe.cornu@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20230515123818.93971-1-raphael.gallais-pou@xxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 03c6becda795c..b8be4c1db4235 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -1145,7 +1145,7 @@ static void ltdc_crtc_disable_vblank(struct drm_crtc *crtc)
static int ltdc_crtc_set_crc_source(struct drm_crtc *crtc, const char *source)
{
- struct ltdc_device *ldev = crtc_to_ltdc(crtc);
+ struct ltdc_device *ldev;
int ret;
DRM_DEBUG_DRIVER("\n");
@@ -1153,6 +1153,8 @@ static int ltdc_crtc_set_crc_source(struct drm_crtc *crtc, const char *source)
if (!crtc)
return -ENODEV;
+ ldev = crtc_to_ltdc(crtc);
+
if (source && strcmp(source, "auto") == 0) {
ldev->crc_active = true;
ret = regmap_set_bits(ldev->regmap, LTDC_GCR, GCR_CRCEN);
