From: Shuah Khan <skhan@linuxfoundation.org>
To: manivannan.sadhasivam@linaro.org, hemantk@codeaurora.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
jhugo@codeaurora.org, sdias@codeaurora.org,
bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Shuah Khan <skhan@linuxfoundation.org>
Subject: bus/mhi/core: Double lock in mhi_device_put() and dev_wake inc/dec
Date: Thu, 17 Sep 2020 17:16:40 -0600 [thread overview]
Message-ID: <5029d4b5-d614-eef3-5a7a-9c8e1c3e7ddb@linuxfoundation.org> (raw)
While looking at this file for an unrelated issue, I happen to notice
there is a double locking on mhi_cntrl->pm_lock in the mhi_device_put()
when it gets called from mhi_driver_remove()
The other two calls from mhi_driver_probe() don't hold the pm_lock.
In addition, lock holding while dev_wake updates is inconsistent.
dev_wake gets incremented and decremented without holding pm_lock in
mhi_device_get(), mhi_device_get_sync() and mhi_device_put().
Exception are when mhi_device_put() is called from mhi_driver_remove().
The following commit is where all this code is added.
bus: mhi: core: Add support for data transfer
https://github.com/torvalds/linux/commit/189ff97cca53e3fe2d8b38d64105040ce17fc62d
It appears to be real problem. I don't have a way to test this driver,
hence reaching out to let you know about my findings.
thanks,
-- Shuah
next reply other threads:[~2020-09-17 23:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 23:16 Shuah Khan [this message]
2020-09-19 2:34 ` bus/mhi/core: Double lock in mhi_device_put() and dev_wake inc/dec bbhatt
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