1 files changed, 9 insertions, 2 deletions

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 3c365ab6cf5f..42e192decbfd 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -656,7 +656,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                  */
                 phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
                 if (paddr == SWIOTLB_MAP_ERROR)
-                        return NULL;
+                        goto err_warn;
 
                 ret = phys_to_virt(paddr);
                 dev_addr = phys_to_dma(hwdev, paddr);
@@ -670,7 +670,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                         /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
                         swiotlb_tbl_unmap_single(hwdev, paddr,
                                                  size, DMA_TO_DEVICE);
-                        return NULL;
+                        goto err_warn;
                 }
         }
 
@@ -678,6 +678,13 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
         memset(ret, 0, size);
 
         return ret;
+
+err_warn:
+        pr_warn("swiotlb: coherent allocation failed for device %s size=%zu\n",
+                dev_name(hwdev), size);
+        dump_stack();
+
+        return NULL;
 }
 EXPORT_SYMBOL(swiotlb_alloc_coherent);