From: Raphael Gallais-Pou <raphael.gallais-pou@xxxxxxxxxxx> [ 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> --- 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); -- 2.39.2
