Re: [PATCH] firmware: Prevent oops on delayed abort

["Luis R. Rodriguez" <mcgrof@kernel.org>]

On Wed, Jan 04, 2017 at 03:47:49PM +0000, Chris Wilson wrote:
> On Wed, Jan 04, 2017 at 04:40:49PM +0100, Luis R. Rodriguez wrote:
> > On Wed, Jan 04, 2017 at 07:12:11PM +0800, Ming Lei wrote:
> > > On Wed, Jan 4, 2017 at 5:31 PM, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> > > > If the firmware load is slow and cancelled, we may call fw_load_abort()
> > > > twice and promptly oops on the second with a NULL dereference.
> > > >
> > > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > > > Cc: Ming Lei <ming.lei@canonical.com>
> > > > Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
> > > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > > ---
> > > >  drivers/base/firmware_class.c | 3 +++
> > > >  1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> > > > index 4497d263209f..d03e21c1d2f3 100644
> > > > --- a/drivers/base/firmware_class.c
> > > > +++ b/drivers/base/firmware_class.c
> > > > @@ -557,6 +557,9 @@ static void fw_load_abort(struct firmware_priv *fw_priv)
> > > >  {
> > > >         struct firmware_buf *buf = fw_priv->buf;
> > > >
> > > > +       if (!buf)
> > > > +               return;
> > > > +
> > > >         __fw_load_abort(buf);
> > > >
> > > >         /* avoid user action after loading abort */
> > > > --
> > > > 2.11.0
> > > >
> > > 
> > > Looks fine,
> > > 
> > > Acked-by: Ming Lei <ming.lei@canonical.com>
> > 
> > But does this fix an actual oops or just theoretical? If it does can you
> > include the trace, and amend the commit log to Cc stable so this gets
> > properly propagated into the stable kernels?
> 
> Actual oops, I was going to include the oops from dmesg but that was
> lost on a the forced reboot. It's fairly clear the cause once you read
> the callers.

I see, if you can reproduce and include it that would be greatly appreciated,
and please re-submit and Cc stable on the commit log, if you can indicate
as of what kernel this is needed even better (Fixes: tag might help).

  Luis