[PATCH 5.18 0735/1095] intel_th: msu-sink: Potential dereference of null pointer

[Greg Kroah-Hartman]

From: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>

[ Upstream commit 82f76a4a720791d889de775b5f7541d601efc8bd ]

The return value of dma_alloc_coherent() needs to be checked.
To avoid use of null pointer in sg_set_buf() in case of the failure of
alloc.

Fixes: f220df66f676 ("intel_th: msu-sink: An example msu buffer "sink"")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220705082637.59979-3-alexander.shishkin@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/hwtracing/intel_th/msu-sink.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwtracing/intel_th/msu-sink.c b/drivers/hwtracing/intel_th/msu-sink.c
index 2c7f5116be12..891b28ea25fe 100644
--- a/drivers/hwtracing/intel_th/msu-sink.c
+++ b/drivers/hwtracing/intel_th/msu-sink.c
@@ -71,6 +71,9 @@ static int msu_sink_alloc_window(void *data, struct sg_table **sgt, size_t size)
 		block = dma_alloc_coherent(priv->dev->parent->parent,
 					   PAGE_SIZE, &sg_dma_address(sg_ptr),
 					   GFP_KERNEL);
+		if (!block)
+			return -ENOMEM;
+
 		sg_set_buf(sg_ptr, block, PAGE_SIZE);
 	}
 
-- 
2.35.1