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From: Loic Poulain <loic.poulain@linaro.org>
To: Bhaumik Bhatt <bbhatt@codeaurora.org>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	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, 9 Feb 2021 19:17:32 +0100	[thread overview]
Message-ID: <CAMZdPi-3PBGLE7KYoSkKWOT7YrbrpA70NRJo2Lrc-MQr=oKUyg@mail.gmail.com> (raw)
In-Reply-To: <7a641d95c2e8c74c7dfc537c74a7ae1a@codeaurora.org>

Hi Bhaumik,

On Tue, 9 Feb 2021 at 18:27, Bhaumik Bhatt <bbhatt@codeaurora.org> wrote:
>
> 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.

Yes, patch [2] is the culprit. I would recommend merging this tiny fix
so that it can be easily grab for 5.11 or backported, and keep your
series (rebased on top), for mhi-next (going to review/test it btw).

Regards,
Loic

  reply	other threads:[~2021-02-09 18:24 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
2021-02-09 18:17       ` Loic Poulain [this message]
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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