Re: [PATCH v1 05/10] bus: mhi: core: Disable IRQs when powering down

From: Manivannan Sadhasivam
Date: Fri Oct 09 2020 - 12:02:25 EST


On Fri, Sep 18, 2020 at 07:02:30PM -0700, Bhaumik Bhatt wrote:
> While powering down, the device may or may not acknowledge the MHI
> RESET issued by host for graceful shutdown scenario which can lead
> to a rogue device sending an interrupt after the clean-up has been
> done. This can result in a tasklet being scheduled after it has
> been killed and access already freed memory causing a NULL pointer
> exception. Avoid this corner case by disabling the interrupts as a
> part of host clean up.
>
> Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
> ---
> drivers/bus/mhi/core/pm.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 1862960..3462d82 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -517,6 +517,7 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
> for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
> if (mhi_event->offload_ev)
> continue;
> + disable_irq(mhi_cntrl->irq[mhi_event->irq]);

No need to disable irq[0]?

Thanks,
Mani

> tasklet_kill(&mhi_event->task);
> }
>
> --
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