bus: mhi: core: Remove MHI event ring IRQ handlers when powering down

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@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index ffbf6f539510f18cebcfa896600798367dc5e825..a671f585ce3590a7f2b97de542f6b7902bd64554 100644 (file)
--- 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 */