@@ -275,6 +275,24 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
EXPORT_SYMBOL(dma_common_mmap);
#ifdef CONFIG_MMU
+static struct vm_struct *__dma_common_pages_remap(struct page **pages,
+ size_t size, unsigned long vm_flags, pgprot_t prot,
+ const void *caller)
+{
+ struct vm_struct *area;
+
+ area = get_vm_area_caller(size, vm_flags, caller);
+ if (!area)
+ return NULL;
+
+ if (map_vm_area(area, prot, pages)) {
+ vunmap(area->addr);
+ return NULL;
+ }
+
+ return area;
+}
+
/*
* remaps an array of PAGE_SIZE pages into another vm_area
* Cannot be used in non-sleeping contexts
@@ -285,17 +303,12 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
{
struct vm_struct *area;
- area = get_vm_area_caller(size, vm_flags, caller);
+ area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
if (!area)
return NULL;
area->pages = pages;
- if (map_vm_area(area, prot, pages)) {
- vunmap(area->addr);
- return NULL;
- }
-
return area->addr;
}
@@ -310,7 +323,7 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
{
int i;
struct page **pages;
- void *ptr;
+ struct vm_struct *area;
pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
if (!pages)
@@ -319,11 +332,13 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
for (i = 0; i < (size >> PAGE_SHIFT); i++)
pages[i] = nth_page(page, i);
- ptr = dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+ area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller);
kfree(pages);
- return ptr;
+ if (!area)
+ return NULL;
+ return area->addr;
}
/*
The dma_common_pages_remap() function allocates a vm_struct object and initialises the pages pointer to value passed as argument. However, when this function is called dma_common_contiguous_remap(), the pages array is only temporarily allocated, being freed shortly after dma_common_contiguous_remap() returns. Architecture code checking the validity of an area->pages pointer would incorrectly dereference already freed pointers. This has been exposed by the arm64 commit 44176bb38fa4 ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU"). Fixes: 513510ddba96 ("common: dma-mapping: introduce common remapping functions") Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reported-by: Andrzej Hajda <a.hajda@samsung.com> Acked-by: Laura Abbott <labbott@redhat.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- Changes since v2: - Rebased to 4.12-rc2 drivers/base/dma-mapping.c | 33 ++++++++++++++++++++++++--------- 1 file changed, 24 insertions(+), 9 deletions(-)