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From: Bhaumik Bhatt <bbhatt@codeaurora.org>
To: Loic Poulain <loic.poulain@linaro.org>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Jeffrey Hugo <jhugo@codeaurora.org>,
	Hemant Kumar <hemantk@codeaurora.org>,
	Kalle Valo <kvalo@codeaurora.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>
Subject: Re: [PATCH] mhi: Fix double dma free
Date: Tue, 09 Feb 2021 09:27:19 -0800	[thread overview]
Message-ID: <7a641d95c2e8c74c7dfc537c74a7ae1a@codeaurora.org> (raw)
In-Reply-To: <CAMZdPi_16SfDoYC0vqqhRfEOqn3SHc6EUmfpVz0RRLaGek7_PQ@mail.gmail.com>

On 2021-02-09 08:06 AM, Loic Poulain wrote:
> On Tue, 9 Feb 2021 at 16:55, Jeffrey Hugo <jhugo@codeaurora.org> wrote:
>> 
>> On 2/9/2021 8:53 AM, Loic Poulain wrote:
>> > mhi_deinit_chan_ctxt functionthat takes care of unitializing channel
>> > resources, including unmapping coherent MHI areas, can be called
>> > from different path in case of controller unregistering/removal:
>> >   - From a client driver remove callback, via mhi_unprepare_channel
>> >   - From mhi_driver_remove that unitialize all channels
>> >
>> > mhi_driver_remove()
>> > |-> driver->remove()
>> > |    |-> mhi_unprepare_channel()
>> > |        |-> mhi_deinit_chan_ctxt()
>> > |...
>> > |-> mhi_deinit_chan_ctxt()
>> >
>> > This leads to double dma freeing...
>> >
>> > Fix that by preventing deinit for already uninitialized channel.
>> >
>> > Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
>> > Reported-by: Kalle Valo <kvalo@codeaurora.org>
>> > ---
>> 
>> Seems like this should have a Fixes: tag, no?
> 
> Right, thanks, i'll add it in V2 once I get feedback.

Hi Loic, Mani,

I saw this same issue a while back but could not collect the logs for 
it.

I had already pushed a patch to fix this differently [1] which was 
recently reviewed by Hemant.

Although there wasn't a purposeful fixes tag for it. I think the culprit 
for this issue is [2]:

As it allows the unprepare to go through on remove(), which was 
traditionally not allowed and
ends up uncovering this issue as it fixes another.

Channel updates [3] address that and provide a bunch of other 
improvements. Please consider them.

Thanks,
Bhaumik

[1] https://lkml.org/lkml/2021/2/4/1161
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/bus/mhi?h=v5.11-rc7&id=a7f422f2f89e7d48aa66e6488444a4c7f01269d5
[3] https://lkml.org/lkml/2021/2/4/1155

---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
Forum,
a Linux Foundation Collaborative Project

  reply	other threads:[~2021-02-09 17:28 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-09 15:53 [PATCH] mhi: Fix double dma free Loic Poulain
2021-02-09 15:55 ` Loic Poulain
2021-02-09 17:02   ` Kalle Valo
2021-02-09 15:55 ` Jeffrey Hugo
2021-02-09 16:06   ` Loic Poulain
2021-02-09 17:27     ` Bhaumik Bhatt [this message]
2021-02-09 18:17       ` Loic Poulain
2021-02-10  4:37         ` Bhaumik Bhatt
2021-02-10  8:17           ` Manivannan Sadhasivam
  -- strict thread matches above, loose matches on Subject: below --
2021-02-09 15:52 Loic Poulain

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