On Sun, Jun 19, 2016 at 02:31:29PM +0200, Mathias Krause wrote:
> The callback function dma_buf_describe() returns an int not void so the
> function pointer cast in dma_buf_show() is wrong. dma_buf_describe() can
> also fail when acquiring the mutex gets interrupted so always returning
> 0 in dma_buf_show() is wrong, too.
>
> Fix both issues by avoiding the indirection via dma_buf_show() and call
> dma_buf_describe() directly. Rename it to dma_buf_debug_show() to get it
> in line with the other functions.
>
> This type mismatch was caught by the PaX RAP plugin.
>
> Signed-off-by: Mathias Krause <minipli at googlemail.com>
> Cc: Sumit Semwal <sumit.semwal at linaro.org>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Brad Spengler <spender at grsecurity.net>
> Cc: PaX Team <pageexec at freemail.hu>
> ---
> drivers/dma-buf/dma-buf.c | 14 +++-----------
> 1 file changed, 3 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 6355ab38d630..7094b19bb495 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -824,7 +824,7 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
> EXPORT_SYMBOL_GPL(dma_buf_vunmap);
>
> #ifdef CONFIG_DEBUG_FS
> -static int dma_buf_describe(struct seq_file *s)
> +static int dma_buf_debug_show(struct seq_file *s, void *unused)
> {
> int ret;
> struct dma_buf *buf_obj;
> @@ -879,17 +879,9 @@ static int dma_buf_describe(struct seq_file *s)
> return 0;
> }
>
> -static int dma_buf_show(struct seq_file *s, void *unused)
> -{
> - void (*func)(struct seq_file *) = s->private;
> -
> - func(s);
> - return 0;
> -}
> -
> static int dma_buf_debug_open(struct inode *inode, struct file *file)
> {
> - return single_open(file, dma_buf_show, inode->i_private);
> + return single_open(file, dma_buf_debug_show, NULL);
> }
>
> static const struct file_operations dma_buf_debug_fops = {
> @@ -913,7 +905,7 @@ static int dma_buf_init_debugfs(void)
> return err;
> }
>
> - err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
> + err = dma_buf_debugfs_create_file("bufinfo", NULL);
This indirection now doesn't make much sense I think. I think more
sensible to instead pass drm_buf_debug_show, since that's the
parametrization that matters. Or just inline that one too.
-Daniel
>
> if (err)
> pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
> --
> 1.7.10.4
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
