On 7/20/2022 4:04 AM, Qiang Yu wrote:
The irq handler for a shared IRQ ought to be prepared for running
even now it's being freed. So let's check the pointer used by
mhi_irq_handler to avoid null pointer access since it is probably
released before freeing IRQ.
Signed-off-by: Qiang Yu <quic_qianyu@xxxxxxxxxxx>
---
drivers/bus/mhi/host/main.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index f3aef77a..7959457 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -430,12 +430,20 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev)
{
struct mhi_event *mhi_event = dev;
struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl;
- struct mhi_event_ctxt *er_ctxt =
- &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index];
+ struct mhi_event_ctxt *er_ctxt;
struct mhi_ring *ev_ring = &mhi_event->ring;
- dma_addr_t ptr = le64_to_cpu(er_ctxt->rp);
+ dma_addr_t ptr;
void *dev_rp;
+ if (!mhi_cntrl->mhi_ctxt) {
+ dev_err(&mhi_cntrl->mhi_dev->dev,
+ "mhi_ctxt has been freed\n");
dev_dbg since you identified a scenario where this is expected?
+ return IRQ_HANDLED;
+ }
+
+ er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index];
+ ptr = le64_to_cpu(er_ctxt->rp);
+
if (!is_valid_ring_ptr(ev_ring, ptr)) {
dev_err(&mhi_cntrl->mhi_dev->dev,
"Event ring rp points outside of the event ring\n");
