net/ena/base: fix metrics excessive memory consumption

[ upstream commit c8a1898 ]

The driver accidentally allocates a huge memory
buffer for the customer metrics because it uses
an uninitialized variable for the buffer length.
This can lead to excessive memory footprint for
the driver which can even fail to initialize in
case of insufficient memory.

Bugzilla ID: 1400
Fixes: f73f53f ("net/ena: upgrade HAL")
Cc: [email protected]

Signed-off-by: Shai Brandes <[email protected]>
Reviewed-by: Amit Bernstein <[email protected]>

drivers/net/ena/base/ena_com.c

@@ -3141,16 +3141,18 @@ int ena_com_allocate_debug_area(struct ena_com_dev *ena_dev,
 int ena_com_allocate_customer_metrics_buffer(struct ena_com_dev *ena_dev)
 {
 	struct ena_customer_metrics *customer_metrics = &ena_dev->customer_metrics;
+	customer_metrics->buffer_len = ENA_CUSTOMER_METRICS_BUFFER_SIZE;
+	customer_metrics->buffer_virt_addr = NULL;
 
 	ENA_MEM_ALLOC_COHERENT(ena_dev->dmadev,
 			       customer_metrics->buffer_len,
 			       customer_metrics->buffer_virt_addr,
 			       customer_metrics->buffer_dma_addr,
 			       customer_metrics->buffer_dma_handle);
-	if (unlikely(customer_metrics->buffer_virt_addr == NULL))
+	if (unlikely(customer_metrics->buffer_virt_addr == NULL)) {
+		customer_metrics->buffer_len = 0;
 		return ENA_COM_NO_MEM;
-
-	customer_metrics->buffer_len = ENA_CUSTOMER_METRICS_BUFFER_SIZE;
+	}
 
 	return 0;
 }