Re: [PATCH 1/2] bdisp: Fix a possible sleep-in-atomic bug in bdisp_hw_reset

[Jia-Ju Bai]

Hi,

On 2017/12/15 22:51, Fabien DESSENNE wrote:
> Hi
>
> On 12/12/17 14:47, Jia-Ju Bai wrote:
> > The driver may sleep under a spinlock.
> > The function call path is:
> > bdisp_device_run (acquire the spinlock)
> >     bdisp_hw_reset
> >       msleep --> may sleep
> >
> > To fix it, msleep is replaced with mdelay.
> May I suggest you to use readl_poll_timeout_atomic (instead of the whole
> "for" block): this fixes the problem and simplifies the code?

Okay, I have submitted a patch according to your advice.
You can have a look :)


Thanks,
Jia-Ju Bai


> > This bug is found by my static analysis tool(DSAC) and checked by my code review.
> >
> > Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
> > ---
> >    drivers/media/platform/sti/bdisp/bdisp-hw.c |    2 +-
> >    1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/sti/bdisp/bdisp-hw.c b/drivers/media/platform/sti/bdisp/bdisp-hw.c
> > index b7892f3..4b62ceb 100644
> > --- a/drivers/media/platform/sti/bdisp/bdisp-hw.c
> > +++ b/drivers/media/platform/sti/bdisp/bdisp-hw.c
> > @@ -382,7 +382,7 @@ int bdisp_hw_reset(struct bdisp_dev *bdisp)
> >    	for (i = 0; i < POLL_RST_MAX; i++) {
> >    		if (readl(bdisp->regs + BLT_STA1) & BLT_STA1_IDLE)
> >    			break;
> > -		msleep(POLL_RST_DELAY_MS);
> > +		mdelay(POLL_RST_DELAY_MS);
> >    	}
> >    	if (i == POLL_RST_MAX)
> >    		dev_err(bdisp->dev, "Reset timeout\n");