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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        Colin Ian King <colin.king@canonical.com>,
        Alex Deucher <alexander.deucher@amd.com>
Subject: [PATCH 5.4 041/244] drm/radeon: fix copy of uninitialized variable back to userspace
Date:   Wed, 12 May 2021 16:46:52 +0200
Message-Id: <20210512144744.364208425@linuxfoundation.org>
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From: Colin Ian King <colin.king@canonical.com>

commit 8dbc2ccac5a65c5b57e3070e36a3dc97c7970d96 upstream.

Currently the ioctl command RADEON_INFO_SI_BACKEND_ENABLED_MASK can
copy back uninitialised data in value_tmp that pointer *value points
to. This can occur when rdev->family is less than CHIP_BONAIRE and
less than CHIP_TAHITI.  Fix this by adding in a missing -EINVAL
so that no invalid value is copied back to userspace.

Addresses-Coverity: ("Uninitialized scalar variable)
Cc: stable@vger.kernel.org # 3.13+
Fixes: 439a1cfffe2c ("drm/radeon: expose render backend mask to the userspace")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/radeon/radeon_kms.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -512,6 +512,7 @@ static int radeon_info_ioctl(struct drm_
 			*value = rdev->config.si.backend_enable_mask;
 		} else {
 			DRM_DEBUG_KMS("BACKEND_ENABLED_MASK is si+ only!\n");
+			return -EINVAL;
 		}
 		break;
 	case RADEON_INFO_MAX_SCLK: