[Qemu-devel] [PATCH v4 07/20] dma: Check iov pointer before unmap memory

[Fam Zheng]

Not all the iov elements are always valid.

Signed-off-by: Fam Zheng <address@hidden>
---
 dma-helpers.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dma-helpers.c b/dma-helpers.c
index 499b52b..3655d88 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -105,6 +105,9 @@ static void dma_bdrv_unmap(DMAAIOCB *dbs)
     int i;
 
     for (i = 0; i < dbs->iov.niov; ++i) {
+        if (!(dbs->iov.iov[i].iov_base && dbs->iov.iov[i].iov_len)) {
+            break;
+        }
         dma_memory_unmap(dbs->sg->as, dbs->iov.iov[i].iov_base,
                          dbs->iov.iov[i].iov_len, dbs->dir,
                          dbs->iov.iov[i].iov_len);
-- 
2.1.0.27.g96db324