net/ena/base: bug fix for 23.11 stable only

From: Shai Brandes <[email protected]>

Hi, the fix is for a bug that was introduced in 23.11.

The fix was already merged into 24.03 indirectly as part of c8a1898f82f8 ("net/ena: improve style and readability") and the entire function was later restructured in patch bcb1753156ac ("net/ena/base: modify customer metrics memory management").

Meaning, this issue is indirectly fixed going forward, but we need to introduce a dedicated fix for 23.11 stable only. I CC'ed also dev mailing list since this involves Bugzilla bug fix.

All the best,
Shai

---
v2:
* reordered the tags in the commit message

Shai Brandes (1):
net/ena/base: fix metrics excessive memory consumption

 drivers/net/ena/base/ena_com.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

2.17.1

From: Shai Brandes <[email protected]>

[ upstream commit c8a1898f82f8c04cbe1d3e2d0eec0705386c23f7 ]

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

---
 drivers/net/ena/base/ena_com.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

index 6953a1fa33..8ae7dcf48e 100644
@@ -3134,16 +3134,18 @@ 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;
 }

2.17.1

Hi Shai,

Thanks for the backporting, patch queued to 23.11.1 staging branch.

________________________________
From: [email protected] <[email protected]>
Sent: Monday, April 8, 2024 8:15 PM
To: [email protected] <[email protected]>; [email protected] <[email protected]>; [email protected] <[email protected]>; Xueming Li <[email protected]>; [email protected] <[email protected]>
Cc: [email protected] <[email protected]>; [email protected] <[email protected]>; Shai Brandes <[email protected]>
Subject: [PATCH v2 1/1] net/ena/base: fix metrics excessive memory consumption

From: Shai Brandes <[email protected]>

[ upstream commit c8a1898f82f8c04cbe1d3e2d0eec0705386c23f7 ]

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

---
 drivers/net/ena/base/ena_com.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

index 6953a1fa33..8ae7dcf48e 100644
@@ -3134,16 +3134,18 @@ 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;
 }

--
2.17.1