fix: crash when not logging all DMA regions

Signed-off-by: William Henderson <william.henderson@nutanix.com>

2 files changed, 6 insertions, 1 deletions

diff --git a/lib/dma.c b/lib/dma.c
index 0d2fe08..c4d8a58 100644
--- a/lib/dma.c
+++ b/lib/dma.c
@@ -804,6 +804,11 @@ dma_controller_dirty_page_get(dma_controller_t *dma, vfu_dma_addr_t addr,
         return ERROR_INT(EINVAL);
     }
 
+    if (region->dirty_bitmap == NULL) {
+        vfu_log(dma->vfu_ctx, LOG_ERR, "region %d is not logged", sg.region);
+        return ERROR_INT(EINVAL);
+    }
+
     for (i = 0; i < (size_t)bitmap_size; i++) {
         uint8_t val = region->dirty_bitmap[i];
         uint8_t *outp = (uint8_t *)&bitmap[i];
diff --git a/lib/dma.h b/lib/dma.h
index f7091f7..55ae72c 100644
--- a/lib/dma.h
+++ b/lib/dma.h
@@ -373,7 +373,7 @@ dma_sgl_put(dma_controller_t *dma, dma_sg_t *sgl, size_t cnt)
         region = &dma->regions[sg->region];
 
         if (sg->writeable) {
-            if (dma->dirty_pgsize > 0) {
+            if (dma->dirty_pgsize > 0 && region->dirty_bitmap != NULL) {
                 _dma_mark_dirty(dma, region, sg);
             }
         }