intel_th: msu-sink: Potential dereference of null pointer

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@linux.intel.com>
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20220705082637.59979-3-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hwtracing/intel_th/msu-sink.c b/drivers/hwtracing/intel_th/msu-sink.c
index 2c7f511..891b28e 100644 (file)
--- 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);
        }