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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, Thierry Reding <thierry.reding@gmail.com>,
        Mikko Perttunen <mperttunen@nvidia.com>,
        dri-devel@lists.freedesktop.org,
        Robin Murphy <robin.murphy@arm.com>,
        Christoph Hellwig <hch@lst.de>,
        Thierry Reding <treding@nvidia.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 257/846] drm/tegra: vic: Fix DMA API misuse
Date:   Mon, 24 Jan 2022 19:36:14 +0100
Message-Id: <20220124184109.800660258@linuxfoundation.org>
In-Reply-To: <20220124184100.867127425@linuxfoundation.org>
References: <20220124184100.867127425@linuxfoundation.org>
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From: Robin Murphy <robin.murphy@arm.com>

[ Upstream commit 5566174cb10a5167d59b0793871cab7990b149b8 ]

Upon failure, dma_alloc_coherent() returns NULL. If that does happen,
passing some uninitialised stack contents to dma_mapping_error() - which
belongs to a different API in the first place - has precious little
chance of detecting it.

Also include the correct header, because the fragile transitive
inclusion currently providing it is going to break soon.

Fixes: 20e7dce255e9 ("drm/tegra: Remove memory allocation from Falcon library")
CC: Thierry Reding <thierry.reding@gmail.com>
CC: Mikko Perttunen <mperttunen@nvidia.com>
CC: dri-devel@lists.freedesktop.org
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/tegra/vic.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/tegra/vic.c b/drivers/gpu/drm/tegra/vic.c
index c02010ff2b7f2..da4af53719917 100644
--- a/drivers/gpu/drm/tegra/vic.c
+++ b/drivers/gpu/drm/tegra/vic.c
@@ -5,6 +5,7 @@
 
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/dma-mapping.h>
 #include <linux/host1x.h>
 #include <linux/iommu.h>
 #include <linux/module.h>
@@ -232,10 +233,8 @@ static int vic_load_firmware(struct vic *vic)
 
 	if (!client->group) {
 		virt = dma_alloc_coherent(vic->dev, size, &iova, GFP_KERNEL);
-
-		err = dma_mapping_error(vic->dev, iova);
-		if (err < 0)
-			return err;
+		if (!virt)
+			return -ENOMEM;
 	} else {
 		virt = tegra_drm_alloc(tegra, size, &iova);
 	}
-- 
2.34.1