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From:   Bhaumik Bhatt <bbhatt@codeaurora.org>
To:     manivannan.sadhasivam@linaro.org
Cc:     linux-arm-msm@vger.kernel.org, hemantk@codeaurora.org,
        jhugo@codeaurora.org, linux-kernel@vger.kernel.org,
        Bhaumik Bhatt <bbhatt@codeaurora.org>
Subject: [PATCH v1 05/10] bus: mhi: core: Disable IRQs when powering down
Date:   Fri, 18 Sep 2020 19:02:30 -0700
Message-Id: <1600480955-16827-6-git-send-email-bbhatt@codeaurora.org>
In-Reply-To: <1600480955-16827-1-git-send-email-bbhatt@codeaurora.org>
References: <1600480955-16827-1-git-send-email-bbhatt@codeaurora.org>
Precedence: bulk

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