On Fri, Oct 09, 2020 at 05:03:37PM +0200, Christian König wrote:
Patch "495c10cc1c0c CHROMIUM: dma-buf: restore args..." adds a workaround for a bug in mmap_region.
As the comment states ->mmap() callback can change vma->vm_file and so we might call fput() on the wrong file.
Revert the workaround and proper fix this in mmap_region.
Signed-off-by: Christian König christian.koenig@amd.com drivers/dma-buf/dma-buf.c | 22 +++++----------------- mm/mmap.c | 2 +- 2 files changed, 6 insertions(+), 18 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index a6ba4d598f0e..edd57402a48a 100644 +++ b/drivers/dma-buf/dma-buf.c @@ -1143,9 +1143,6 @@ EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); 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;
@@ -1163,22 +1160,13 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, return -EINVAL; /* readjust the vma */
- get_file(dmabuf->file);
- oldfile = vma->vm_file;
- vma->vm_file = dmabuf->file;
- vma->vm_pgoff = pgoff;
- if (vma->vm_file)
fput(vma->vm_file);
This if is redundant too
But otherwise
Reviewed-by: Jason Gunthorpe jgg@nvidia.com
Thanks, Jason