There is a potential deadlock scenario in mhi_ep_reset_worker() where
the state_lock mutex is acquired twice in the same call chain:
mhi_ep_reset_worker()
mutex_lock(&mhi_cntrl->state_lock)
mhi_ep_power_up()
mhi_ep_set_ready_state()
mutex_lock(&mhi_cntrl->state_lock) <- Deadlock
Fix this by releasing the state_lock before calling mhi_ep_power_up().
The lock is only needed to protect current MHI state read operation. The
lock can be safely released before proceeding with the power up sequence.
Fixes: 7a97b6b47353 ("bus: mhi: ep: Add support for handling MHI_RESET")
Signed-off-by: Sumit Kumar <sumit.kumar@oss.qualcomm.com>
---
drivers/bus/mhi/ep/main.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index cdea24e9291959ae0a92487c1b9698dc8164d2f1..73597de373ef7e0c428bcbc126d63a9a97f95144 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -1093,6 +1093,7 @@ static void mhi_ep_reset_worker(struct work_struct *work)
mhi_ep_mmio_reset(mhi_cntrl);
cur_state = mhi_cntrl->mhi_state;
+ mutex_unlock(&mhi_cntrl->state_lock);
/*
* Only proceed further if the reset is due to SYS_ERR. The host will
* issue reset during shutdown also and we don't need to do re-init in
@@ -1100,8 +1101,6 @@ static void mhi_ep_reset_worker(struct work_struct *work)
*/
if (cur_state == MHI_STATE_SYS_ERR)
mhi_ep_power_up(mhi_cntrl);
-
- mutex_unlock(&mhi_cntrl->state_lock);
}
/*
--
2.34.1