Re: [PATCH v1 2/2] Fixes: Coverity CID 1558831

[Philippe Mathieu-Daudé]

Back at this patch since Cédric asked me to look at it.

On 6/8/24 15:48, Chalapathi V wrote:
> In this commit the following coverity scan defect has been fixed
> CID 1558831:  Resource leaks  (RESOURCE_LEAK)
>    Variable "rsp_payload" going out of scope leaks the storage it
>    points to.
>
> Signed-off-by: Chalapathi V <chalapathi.v@linux.ibm.com>
> ---
>   hw/ssi/pnv_spi.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/hw/ssi/pnv_spi.c b/hw/ssi/pnv_spi.c
> index a33f682897..dbe06df224 100644
> --- a/hw/ssi/pnv_spi.c
> +++ b/hw/ssi/pnv_spi.c
> @@ -237,6 +237,7 @@ static void transfer(PnvSpi *s, PnvXferBuffer *payload)
>       }
>       if (rsp_payload != NULL) {
>           spi_response(s, s->N1_bits, rsp_payload);
> +        pnv_spi_xfer_buffer_free(rsp_payload);
>       }
>   }
>   

Or bigger patch but simpler logic:

-- >8 --
diff --git a/hw/ssi/pnv_spi.c b/hw/ssi/pnv_spi.c
index c1297ab733..aaedba84af 100644
--- a/hw/ssi/pnv_spi.c
+++ b/hw/ssi/pnv_spi.c
@@ -217,6 +217,9 @@ static void transfer(PnvSpi *s, PnvXferBuffer *payload)
     PnvXferBuffer *rsp_payload = NULL;

     rsp_payload = pnv_spi_xfer_buffer_new();
+    if (!rsp_payload) {
+        return;
+    }
     for (int offset = 0; offset < payload->len; offset += 
s->transfer_len) {
         tx = 0;
         for (int i = 0; i < s->transfer_len; i++) {
@@ -235,9 +238,8 @@ static void transfer(PnvSpi *s, PnvXferBuffer *payload)
                     (rx >> (8 * (s->transfer_len - 1) - i * 8)) & 0xFF;
         }
     }
-    if (rsp_payload != NULL) {
-        spi_response(s, s->N1_bits, rsp_payload);
-    }
+    spi_response(s, s->N1_bits, rsp_payload);
+    pnv_spi_xfer_buffer_free(rsp_payload);
 }

---

I note few things is odd here:

1/ pnv_spi_xfer_buffer_new() uses the GLib g_malloc0() call
   while pnv_spi_xfer_buffer_free() uses plan free().

2/ pnv_spi_xfer_buffer_free() frees payload->data so doesn't
   match pnv_spi_xfer_buffer_new().

This is a bit disappointing.