Pointer of struct *drm_crtc was dereferenced before checking it was non NULL. This could potentially create a kernel panic.

Fixes: 79b44684a14e ("drm/stm: ltdc: add support for CRC hashing feature") Reported-by: kernel test robot lkp@intel.com Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Raphael Gallais-Pou raphael.gallais-pou@foss.st.com --- 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 6bd45df8f5a7..9c0fadd58d2a 100644 --- a/drivers/gpu/drm/stm/ltdc.c +++ b/drivers/gpu/drm/stm/ltdc.c @@ -1120,7 +1120,7 @@ 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"); @@ -1128,6 +1128,8 @@ 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);