On 03/09/2020 16:50, [email protected] wrote:
> From: Tom Rix <[email protected]>
>
> clang static analyzer reports this problem
>
> em28xx-core.c:1162:4: warning: Called function pointer
> is null (null dereference)
> ops->suspend(dev->dev_next);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> This is the problem block
>
> if (ops->suspend)
> ops->suspend(dev);
> if (dev->dev_next)
> ops->suspend(dev->dev_next);
>
> The check for ops->suspend only covers one statement.
> So fix the check consistent with other similar in
> the file.
>
> Change a similar check in em28xx_resume_extension()
> to use consistent logic as its siblings.
>
> Fixes: be7fd3c3a8c5 ("media: em28xx: Hauppauge DualHD second tuner
> functionality")
> Signed-off-by: Tom Rix <[email protected]>
> ---
> drivers/media/usb/em28xx/em28xx-core.c | 17 +++++++++--------
> 1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/usb/em28xx/em28xx-core.c
> b/drivers/media/usb/em28xx/em28xx-core.c
> index e6088b5d1b80..d60f4c2a661d 100644
> --- a/drivers/media/usb/em28xx/em28xx-core.c
> +++ b/drivers/media/usb/em28xx/em28xx-core.c
> @@ -1156,10 +1156,11 @@ int em28xx_suspend_extension(struct em28xx *dev)
> dev_info(&dev->intf->dev, "Suspending extensions\n");
> mutex_lock(&em28xx_devlist_mutex);
> list_for_each_entry(ops, &em28xx_extension_devlist, next) {
> - if (ops->suspend)
> + if (ops->suspend) {
> ops->suspend(dev);
> - if (dev->dev_next)
> - ops->suspend(dev->dev_next);
> + if (dev->dev_next)
> + ops->suspend(dev->dev_next);
> + }
> }
> mutex_unlock(&em28xx_devlist_mutex);
> return 0;
> @@ -1172,11 +1173,11 @@ int em28xx_resume_extension(struct em28xx *dev)
> dev_info(&dev->intf->dev, "Resuming extensions\n");
> mutex_lock(&em28xx_devlist_mutex);
> list_for_each_entry(ops, &em28xx_extension_devlist, next) {
> - if (!ops->resume)
> - continue;
Actually, this code is fine: if !ops->resume, then just continue.
So there is no need to change this resume code.
And in fact, I think it would be best if the same approach was used in
em28xx_suspend_extension.
Regards,
Hans
> - ops->resume(dev);
> - if (dev->dev_next)
> - ops->resume(dev->dev_next);
> + if (ops->resume) {
> + ops->resume(dev);
> + if (dev->dev_next)
> + ops->resume(dev->dev_next);
> + }
> }
> mutex_unlock(&em28xx_devlist_mutex);
> return 0;
>
