Re: [PATCH] block/nvme: Remove memory leak

[Philippe Mathieu-Daudé]

On 4/15/20 9:46 AM, Stefano Garzarella wrote:

On Tue, Apr 14, 2020 at 05:17:26PM +0200, Philippe Mathieu-Daudé wrote:

Fixes: bdd6a90a9 ("Add VFIO based NVMe driver")
Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
  block/nvme.c | 1 +
  1 file changed, 1 insertion(+)

diff --git a/block/nvme.c b/block/nvme.c
index 7b7c0cc5d6..9f3c7ab819 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -163,6 +163,7 @@ static void nvme_init_queue(BlockDriverState *bs, NVMeQueue 
*q,
      }
      r = qemu_vfio_dma_map(s->vfio, q->queue, bytes, false, &q->iova);
      if (r) {
+        qemu_vfree(q->queue);
          error_setg(errp, "Cannot map queue");
      }
  }
--
2.21.1

Are we adding a double free with this change?

IIUC when nvme_init_queue() fails in the nvme_create_queue_pair() we
already call the nvme_free_queue_pair() that frees sq.queue and
cq.queue.

Argh you are right, I missed that...

I think your patch make the code cleaner, freeing the buffer near the
allocation during an error, maybe we can also set q->queue to NULL
after the qemu_vfree().

Thanks,
Stefano