dma-debug: warn of unmapping an invalid dma address

Impact: extend DMA-debug checks

Calling dma_unmap families against an invalid dma address should be a
bug.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Joerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20090319103743N.fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 9a350b414a50..f9e6d38b4b34 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -531,8 +531,11 @@ static void check_unmap(struct dma_debug_entry *ref)
         struct hash_bucket *bucket;
         unsigned long flags;
 
-        if (dma_mapping_error(ref->dev, ref->dev_addr))
+        if (dma_mapping_error(ref->dev, ref->dev_addr)) {
+                err_printk(ref->dev, NULL, "DMA-API: device driver tries "
+                           "to free an invalid DMA memory address\n");
                 return;
+        }
 
         bucket = get_hash_bucket(ref, &flags);
         entry = hash_bucket_find(bucket, ref);