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Date:   Fri, 9 Oct 2020 21:32:16 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To:     Bhaumik Bhatt <bbhatt@codeaurora.org>
Cc:     linux-arm-msm@vger.kernel.org, hemantk@codeaurora.org,
        jhugo@codeaurora.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 05/10] bus: mhi: core: Disable IRQs when powering down
Message-ID: <20201009160216.GF4810@Mani-XPS-13-9360>
References: <1600480955-16827-1-git-send-email-bbhatt@codeaurora.org>
 <1600480955-16827-6-git-send-email-bbhatt@codeaurora.org>
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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@codeaurora.org>
> ---
>  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);
>  	}
>  
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>