Re: [PATCH] media: renesas: vsp1: Fix _irqsave and _irq mix

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Tue, May 07, 2024 at 11:11:25AM +0300, Sergei Shtylyov wrote:
> On 5/5/24 8:45 PM, Laurent Pinchart wrote:
> 
> > The histogram support mixes _irqsave and _irq, causing the following
> > smatch warning:
> > 
> >      drivers/media/platform/renesas/vsp1/vsp1_histo.c:153 histo_stop_streaming()
> >      warn: mixing irqsave and irq
> > 
> > The histo_stop_streaming() calls spin_lock_irqsave() followed by
> > wait_event_lock_irq(). The former hints that interrupts may be disabled
> > by the caller, while the latter reenables interrupts unconditionally.
> > This doesn't cause any real bug, as the function is always called with
> > interrupts enabled, but the pattern is still in correct.
> 
>    Incorrect? :-)

Oops :-) I'll fix it, but will likely not send a new version if that's
the only issue.

> > Fix the problem by using spin_lock_irq() instead of spin_lock_irqsave()
> > in histo_stop_streaming(). While at it, switch to spin_lock_irq() and
> > spin_lock() as appropriate elsewhere.
> > 
> > Fixes: 99362e32332b ("[media] v4l: vsp1: Add histogram support")
> > Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> > Closes: https://lore.kernel.org/linux-renesas-soc/164d74ff-312c-468f-be64-afa7182cd2f4@moroto.mountain/
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> > ---
> >  .../media/platform/renesas/vsp1/vsp1_histo.c  | 20 ++++++++-----------
> >  1 file changed, 8 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/media/platform/renesas/vsp1/vsp1_histo.c b/drivers/media/platform/renesas/vsp1/vsp1_histo.c
> > index 71155282ca11..cd1c8778662e 100644
> > --- a/drivers/media/platform/renesas/vsp1/vsp1_histo.c
> > +++ b/drivers/media/platform/renesas/vsp1/vsp1_histo.c
> [...]
> 
> MBR, Sergey

-- 
Regards,

Laurent Pinchart