Re: [PATCH v1 05/10] bus: mhi: core: Disable IRQs when powering down
From: Bhaumik Bhatt
Date: Mon Oct 12 2020 - 20:06:23 EST
On 2020-10-09 09:02, Manivannan Sadhasivam wrote:
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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This patch would disable the IRQ line and if IRQ lines are shared
between BHI
and MHI, we would not see handling of BHI related work happen.
Discussed this with Hemant and and as I am dropping the previous patch,
will update
this one to make it free_irq() instead which removes the IRQ handler and
does not
disable the interrupt line.
The function mhi_deinit_free_irq() will not be called from
mhi_power_down() and
instead, only a free for the main IRQ handler will be called.
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project