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 --- a/drivers/dma-buf/dma-buf.c +++ 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);
- 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; + vma->vm_file = get_file(dmabuf->file); + vma->vm_pgoff = pgoff;
+ return dmabuf->ops->mmap(dmabuf, vma); } EXPORT_SYMBOL_GPL(dma_buf_mmap);
diff --git a/mm/mmap.c b/mm/mmap.c index 40248d84ad5f..3a2670d73355 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1852,8 +1852,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, return addr;
unmap_and_free_vma: + fput(vma->vm_file); vma->vm_file = NULL; - fput(file);
/* Undo any partial mapping done by a device driver. */ unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);