2023-10-03 09:14:15

by Ma Ke

Subject: [PATCH v2] media: videobuf2: Fix IS_ERR checking in vb2_vmalloc_put_userptr()

In order to avoid error pointers from frame_vector_pages(), we could
use IS_ERR() to check the return value to fix this. This checking
operation could make sure that vector contains pages.

Signed-off-by: Ma Ke <[email protected]>
---
drivers/media/common/videobuf2/videobuf2-vmalloc.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
index 7c635e292106..5aa66305546d 100644
--- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
+++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
@@ -133,13 +133,15 @@ static void vb2_vmalloc_put_userptr(void *buf_priv)

if (!buf->vec->is_pfns) {
n_pages = frame_vector_count(buf->vec);
- pages = frame_vector_pages(buf->vec);
if (vaddr)
vm_unmap_ram((void *)vaddr, n_pages);
if (buf->dma_dir == DMA_FROM_DEVICE ||
- buf->dma_dir == DMA_BIDIRECTIONAL)
- for (i = 0; i < n_pages; i++)
- set_page_dirty_lock(pages[i]);
+ buf->dma_dir == DMA_BIDIRECTIONAL){
+ pages = frame_vector_pages(buf->vec);
+ if (!WARN_ON_ONCE(IS_ERR(pages)))
+ for (i = 0; i < n_pages; i++)
+ set_page_dirty_lock(pages[i]);
+ }
} else {
iounmap((__force void __iomem *)buf->vaddr);
}
--
2.37.2

2023-10-12 06:18:01

by Tomasz Figa

Subject: Re: [PATCH v2] media: videobuf2: Fix IS_ERR checking in vb2_vmalloc_put_userptr()

On Tue, Oct 3, 2023 at 6:13 PM Ma Ke <[email protected]> wrote:
>
> In order to avoid error pointers from frame_vector_pages(), we could
> use IS_ERR() to check the return value to fix this. This checking
> operation could make sure that vector contains pages.
>
> Signed-off-by: Ma Ke <[email protected]>
> ---
> drivers/media/common/videobuf2/videobuf2-vmalloc.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> index 7c635e292106..5aa66305546d 100644
> --- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> +++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
> @@ -133,13 +133,15 @@ static void vb2_vmalloc_put_userptr(void *buf_priv)
>
> if (!buf->vec->is_pfns) {
> n_pages = frame_vector_count(buf->vec);
> - pages = frame_vector_pages(buf->vec);
> if (vaddr)
> vm_unmap_ram((void *)vaddr, n_pages);
> if (buf->dma_dir == DMA_FROM_DEVICE ||
> - buf->dma_dir == DMA_BIDIRECTIONAL)
> - for (i = 0; i < n_pages; i++)
> - set_page_dirty_lock(pages[i]);
> + buf->dma_dir == DMA_BIDIRECTIONAL){

Missing space between ) and { .

> + pages = frame_vector_pages(buf->vec);
> + if (!WARN_ON_ONCE(IS_ERR(pages)))

I still think this cannot happen, but the frame vector code is a mess,
so being a bit more defensive here is probably fine, until someone can
clean up that code (probably by removing the PFN-only code path
completely).

> + for (i = 0; i < n_pages; i++)
> + set_page_dirty_lock(pages[i]);
> + }
> } else {
> iounmap((__force void __iomem *)buf->vaddr);
> }
> --
> 2.37.2
>

With that one formatting issue fixed: (Mauro, Hans, maybe it could be
fixed up when applying?)

Acked-by: Tomasz Figa <[email protected]>

Best regards,
Tomasz