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From 71225e1c930942cb1e042fc08c5cc0c4ef30e95e Mon Sep 17 00:00:00 2001
From: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Date: Tue, 8 Aug 2023 11:04:16 -0700
Subject: [PATCH] drm/radeon: check return value of radeon_ring_lock()
Git-commit: 71225e1c930942cb1e042fc08c5cc0c4ef30e95e
Patch-mainline: v6.8-rc1
References: git-fixes

In the unlikely event of radeon_ring_lock() failing, its errno return
value should be processed. This patch checks said return value and
prints a debug message in case of an error.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 48c0c902e2e6 ("drm/radeon/kms: add support for CP setup on SI")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/radeon/si.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index a91012447b56..85e9cba49cec 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -3611,6 +3611,10 @@ static int si_cp_start(struct radeon_device *rdev)
 	for (i = RADEON_RING_TYPE_GFX_INDEX; i <= CAYMAN_RING_TYPE_CP2_INDEX; ++i) {
 		ring = &rdev->ring[i];
 		r = radeon_ring_lock(rdev, ring, 2);
+		if (r) {
+			DRM_ERROR("radeon: cp failed to lock ring (%d).\n", r);
+			return r;
+		}
 
 		/* clear the compute context state */
 		radeon_ring_write(ring, PACKET3_COMPUTE(PACKET3_CLEAR_STATE, 0));
-- 
2.35.3