Re: [PATCH 01/16] clk: fix critical clock locking

Maxime Ripard
2016-05-13T07:50:00Z

[-- Attachment #1: Type: text/plain, Size: 1561 bytes --]

Hi Stephen,

On Mon, May 09, 2016 at 03:11:46PM -0700, Stephen Boyd wrote:
> On 05/08, Maxime Ripard wrote:
> > The critical clock handling in __clk_core_init isn't taking the enable lock
> > before calling clk_core_enable, which in turns triggers the warning in the
> > lockdep_assert_held call in that function when lockep is enabled.
> >
> > Add the calls to clk_enable_lock/unlock to make sure it doesn't happen.
> >
> > Fixes: 32b9b1096186 ("clk: Allow clocks to be marked as CRITICAL")
> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > ---
>
> Why is this patch hiding in this series?

Sorry, I discovered it while working on this, and somehow it slipped
in there. I'll resend it separately.

>
> > drivers/clk/clk.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index ce39add5a258..16a38df3c688 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -2404,8 +2404,15 @@ static int __clk_core_init(struct clk_core *core)
> > core->ops->init(core->hw);
> >
> > if (core->flags & CLK_IS_CRITICAL) {
> > + unsigned long flags;
> > +
> > + clk_prepare_lock();
> > clk_core_prepare(core);
> > + clk_prepare_unlock();
>
> It looks like we already hold the prepare lock at this point.

You're right. I thought I removed it, but obviously I didn't.

I'll send a v2.

Thanks!
Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]