[PATCH] staging: vchiq: silence an uninitialized variable warning

[Arnd Bergmann]

On Wed, Sep 30, 2020 at 11:02 AM Dan Carpenter <dan.carpenter at oracle.com> wrote:
>
> Smatch complains that "userdata" can be passed to vchiq_bulk_transfer()
> without being initialized.  Smatch is correct, however, in that
> situation the "userdata" is not used so it doesn't cause a problem.
> Passing an uninitialized variable will trigger a UBSan warning at
> runtime so this warning is worth silencing by setting "userdata" to
> NULL.
>
> Fixes: a4367cd2b231 ("staging: vchiq: convert compat bulk transfer")
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>

The change looks fine, but I wonder if it's actually worse and the
uninitialized pointer can end up getting copied back to user space
in the completion.

In either case, thanks for the fix!

Acked-by: Arnd Bergmann <arnd at arndb.de>