From: John Sheu <sheu@xxxxxxxxxxxx>
Callers to dma_buf_mmap expect to fput() the vma struct's vm_file
themselves on failure. Not restoring the struct's data on failure
causes a double-decrement of the vm_file's refcount.
Signed-off-by: John Sheu <sheu@xxxxxxxxxx>
---
drivers/base/dma-buf.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index a3f79c4..01daf9c 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -446,6 +446,9 @@ EXPORT_SYMBOL_GPL(dma_buf_kunmap);
int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
unsigned long pgoff)
{
+ struct file *oldfile;
+ int ret;
+
if (WARN_ON(!dmabuf || !vma))
return -EINVAL;
@@ -459,14 +462,21 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
return -EINVAL;
/* readjust the vma */
- if (vma->vm_file)
- fput(vma->vm_file);
-
+ oldfile = vma->vm_file;
vma->vm_file = get_file(dmabuf->file);
vma->vm_pgoff = pgoff;
- return dmabuf->ops->mmap(dmabuf, vma);
+ ret = dmabuf->ops->mmap(dmabuf, vma);
+ if (ret) {
+ /* restore old parameters on failure */
+ vma->vm_file = oldfile;
+ fput(dmabuf->file);
+ } else {
+ if (oldfile)
+ fput(oldfile);
+ }
+ return ret;
}
EXPORT_SYMBOL_GPL(dma_buf_mmap);
--
1.8.1
--
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