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bus: mhi: ep: Fix potential deadlock in mhi_ep_reset_worker()

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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: 7a97b6b473 ("bus: mhi: ep: Add support for handling MHI_RESET")
Signed-off-by: Sumit Kumar <sumit.kumar@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Link: https://patch.msgid.link/20260414-reset_worker_deadlock-v2-1-42fd682b45db@oss.qualcomm.com
This commit is contained in:
Sumit Kumar
2026-04-14 11:59:40 +05:30
committed by Manivannan Sadhasivam
parent 86f6dc05ea
commit 9dece4435d
1 changed files with 3 additions and 4 deletions
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7
drivers/bus/mhi/ep/main.c
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@@ -1087,11 +1087,12 @@ static void mhi_ep_reset_worker(struct work_struct *work)
mhi_ep_power_down(mhi_cntrl);
mutex_lock(&mhi_cntrl->state_lock);
/* Reset MMIO to signal host that the MHI_RESET is completed in endpoint */
mhi_ep_mmio_reset(mhi_cntrl);
mutex_lock(&mhi_cntrl->state_lock);
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
@@ -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);
}
/*