[Intel-gfx] [PATCH] drm/i915/icl: Prevent possibe de-reference in skl_check_pipe_max_pixel_clock.

[clinton.a.taylor at intel.com]

From: Clint Taylor <clinton.a.taylor at intel.com>

Add protections to prevent NULL de-reference for a couple variables used
in skl_check_pipe_max_pixel_clock to prevent GP exception from occurring
during some IGT tests.

References: https://bugs.freedesktop.org/show_bug.cgi?id=109084

Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Martin Peres <martin.peres at linux.intel.com>
Signed-off-by: Clint Taylor <clinton.a.taylor at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 4 ++++
 drivers/gpu/drm/i915/intel_pm.c      | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3bd40a4a6739..945861cef520 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11377,6 +11377,10 @@ static int intel_crtc_atomic_check(struct drm_crtc *crtc,
 
 		if (!ret)
 			ret = icl_check_nv12_planes(pipe_config);
+
+		if (WARN_ON(!intel_crtc))
+			return -EINVAL;
+
 		if (!ret)
 			ret = skl_check_pipe_max_pixel_rate(intel_crtc,
 							    pipe_config);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 7357bddf9ad9..df5d01d4345b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4160,6 +4160,9 @@ int skl_check_pipe_max_pixel_rate(struct intel_crtc *intel_crtc,
 		uint_fixed_16_16_t fp_9_div_8 = div_fixed16(9, 8);
 		int bpp;
 
+		if (WARN_ON(!pstate))
+			return -EINVAL;
+
 		if (!intel_wm_plane_visible(cstate,
 					    to_intel_plane_state(pstate)))
 			continue;
-- 
2.19.1