| From ccf1f461e5d2a7950620f07017b8e72d84805cec Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 15 May 2023 14:38:18 +0200 |
| Subject: drm/stm: ltdc: fix late dereference check |
| |
| From: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com> |
| |
| [ 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@intel.com> |
| Closes: https://lore.kernel.org/lkml/202212241802.zeLFZCXB-lkp@intel.com/ |
| Reported-by: Dan Carpenter <error27@gmail.com> |
| Closes: https://lore.kernel.org/lkml/202212241802.zeLFZCXB-lkp@intel.com/ |
| Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com> |
| Acked-by: Philippe Cornu <philippe.cornu@foss.st.com> |
| Signed-off-by: Philippe Cornu <philippe.cornu@foss.st.com> |
| Link: https://patchwork.freedesktop.org/patch/msgid/20230515123818.93971-1-raphael.gallais-pou@foss.st.com |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/gpu/drm/stm/ltdc.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| 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); |
| -- |
| 2.40.1 |
| |
