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From:   Nikita Zhandarovich <n.zhandarovich@fintech.ru>
To:     Alex Deucher <alexander.deucher@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>
CC:     Nikita Zhandarovich <n.zhandarovich@fintech.ru>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Dave Airlie <airlied@redhat.com>,
        <amd-gfx@lists.freedesktop.org>, <dri-devel@lists.freedesktop.org>,
        <linux-kernel@vger.kernel.org>, <lvc-project@linuxtesting.org>
Subject: [PATCH] drm/radeon: check return value of radeon_ring_lock()
Date:   Tue, 8 Aug 2023 11:04:16 -0700
Message-ID: <20230808180416.7567-1-n.zhandarovich@fintech.ru>
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Precedence: bulk

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>
---
 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 8d5e4b25609d..df1b2ebc37c2 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));
-- 
2.25.1