[PATCH v3 12/12] bus: mhi: core: Remove MHI event ring IRQ handlers when powering down

[Bhaumik Bhatt]

While powering down, the device may or may not acknowledge an MHI
RESET issued by host for a graceful shutdown scenario and end up
sending an incoming data packet after tasklets have been killed.
If a rogue device sends this interrupt for a data transfer event
ring update, it can result in a tasklet getting scheduled while a
clean up is ongoing or has completed and cause access to freed
memory leading to a NULL pointer exception. Remove the interrupt
handlers for MHI event rings early on to avoid this scenario.

Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
---
 drivers/bus/mhi/core/pm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index ffbf6f5..a671f58 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -494,6 +494,7 @@ 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;
+		free_irq(mhi_cntrl->irq[mhi_event->irq], mhi_event);
 		tasklet_kill(&mhi_event->task);
 	}
 
@@ -1164,7 +1165,7 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
 	/* Wait for shutdown to complete */
 	flush_work(&mhi_cntrl->st_worker);
 
-	mhi_deinit_free_irq(mhi_cntrl);
+	free_irq(mhi_cntrl->irq[0], mhi_cntrl);
 
 	if (!mhi_cntrl->pre_init) {
 		/* Free all allocated resources */
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project