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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Shuah Khan <skhan@linuxfoundation.org>,
        Bhaumik Bhatt <bbhatt@codeaurora.org>,
        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 150/717] bus: mhi: core: Remove double locking from mhi_driver_remove()
Date:   Mon, 28 Dec 2020 13:42:28 +0100
Message-Id: <20201228125028.151067722@linuxfoundation.org>
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From: Bhaumik Bhatt <bbhatt@codeaurora.org>

[ Upstream commit 9b627c25e70816a5e1dca940444b5029065b4d60 ]

There is double acquisition of the pm_lock from mhi_driver_remove()
function. Remove the read_lock_bh/read_unlock_bh calls for pm_lock
taken during a call to mhi_device_put() as the lock is acquired
within the function already. This will help avoid a potential
kernel panic.

Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer")
Reported-by: Shuah Khan <skhan@linuxfoundation.org>
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/bus/mhi/core/init.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 0ffdebde82657..0a09f8215057d 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -1276,10 +1276,8 @@ static int mhi_driver_remove(struct device *dev)
 		mutex_unlock(&mhi_chan->mutex);
 	}
 
-	read_lock_bh(&mhi_cntrl->pm_lock);
 	while (mhi_dev->dev_wake)
 		mhi_device_put(mhi_dev);
-	read_unlock_bh(&mhi_cntrl->pm_lock);
 
 	return 0;
 }
-- 
2.27.0