[PATCH] drm/i915/display: fix missing null check on allocated dsb object

* [PATCH] drm/i915/display: fix missing null check on allocated dsb object
@ 2020-06-16 11:42 Colin King
  2020-06-16 11:54 ` Dan Carpenter
  0 siblings, 1 reply; 4+ messages in thread
From: Colin King @ 2020-06-16 11:42 UTC (permalink / raw)
  To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, David Airlie,
	Daniel Vetter, Animesh Manna, Maarten Lankhorst, intel-gfx,
	dri-devel
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

Currently there is no null check for a failed memory allocation
on the dsb object and without this a null pointer dereference
error can occur. Fix this by adding a null check.

Note: added a drm_err message in keeping with the error message style
in the function.

Addresses-Coverity: ("Dereference null return")
Fixes: afeda4f3b1c8 ("drm/i915/dsb: Pre allocate and late cleanup of cmd buffer")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/gpu/drm/i915/display/intel_dsb.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index 24e6d63e2d47..566fa72427b3 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -271,6 +271,10 @@ void intel_dsb_prepare(struct intel_crtc_state *crtc_state)
 		return;
 
 	dsb = kmalloc(sizeof(*dsb), GFP_KERNEL);
+	if (!dsb) {
+		drm_err(&i915->drm, "DSB object creation failed\n");
+		return;
+	}
 
 	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
 
-- 
2.27.0.rc0

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