With spin_lock_bh(), it is possible that a tasklet processing data events gets scheduled out if another higher priority tasklet is ready to run. While the tasklet is sleeping, it can hold the event ring spinlock and block another tasklet, for example, one processing an M0 state change event, from acquiring it. This can starve the core which blocks in an attempt to acquire the spinlock until it gets released. Fix this issue by disabling pre-emption on the core processing data events and allow it to run to completion such that other tasklets do not block for long periods. Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device") Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx> --- drivers/bus/mhi/core/main.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index 3775c77..02c8c09 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -1036,11 +1036,12 @@ void mhi_ev_task(unsigned long data) { struct mhi_event *mhi_event = (struct mhi_event *)data; struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl; + unsigned long flags; /* process all pending events */ - spin_lock_bh(&mhi_event->lock); + spin_lock_irqsave(&mhi_event->lock, flags); mhi_event->process_event(mhi_cntrl, mhi_event, U32_MAX); - spin_unlock_bh(&mhi_event->lock); + spin_unlock_irqrestore(&mhi_event->lock, flags); } void mhi_ctrl_ev_task(unsigned long data) -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project