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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Chris Lew <quic_clew@quicinc.com>
Cc: Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	 Sibi Sankar <quic_sibis@quicinc.com>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	 linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-remoteproc@vger.kernel.org,
	Johan Hovold <johan+linaro@kernel.org>,
	 Xilin Wu <wuxilin123@gmail.com>,
	"Bryan O'Donoghue" <bryan.odonoghue@linaro.org>,
	 Neil Armstrong <neil.armstrong@linaro.org>
Subject: Re: [PATCH v7 1/6] soc: qcom: pdr: protect locator_addr with the main mutex
Date: Sun, 12 May 2024 00:52:23 +0300	[thread overview]
Message-ID: <CAA8EJpoNQy682GDfWZpKz2McE=ho0YQXperE2Mi1Wk=OFkJb3g@mail.gmail.com> (raw)
In-Reply-To: <d71c677f-eff7-2bc4-4328-38e4d83e1115@quicinc.com>

On Thu, 25 Apr 2024 at 22:30, Chris Lew <quic_clew@quicinc.com> wrote:
>
>
> On 4/24/2024 2:27 AM, Dmitry Baryshkov wrote:
> > If the service locator server is restarted fast enough, the PDR can
> > rewrite locator_addr fields concurrently. Protect them by placing
> > modification of those fields under the main pdr->lock.
> >
> > Fixes: fbe639b44a82 ("soc: qcom: Introduce Protection Domain Restart helpers")
> > Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > ---
> >   drivers/soc/qcom/pdr_interface.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/soc/qcom/pdr_interface.c b/drivers/soc/qcom/pdr_interface.c
> > index a1b6a4081dea..19cfe4b41235 100644
> > --- a/drivers/soc/qcom/pdr_interface.c
> > +++ b/drivers/soc/qcom/pdr_interface.c
> > @@ -76,12 +76,12 @@ static int pdr_locator_new_server(struct qmi_handle *qmi,
> >                                             locator_hdl);
> >       struct pdr_service *pds;
> >
> > +     mutex_lock(&pdr->lock);
> >       /* Create a local client port for QMI communication */
> >       pdr->locator_addr.sq_family = AF_QIPCRTR;
> >       pdr->locator_addr.sq_node = svc->node;
> >       pdr->locator_addr.sq_port = svc->port;
> >
> > -     mutex_lock(&pdr->lock);
> >       pdr->locator_init_complete = true;
> >       mutex_unlock(&pdr->lock);
> >
> > @@ -104,10 +104,10 @@ static void pdr_locator_del_server(struct qmi_handle *qmi,
> >
> >       mutex_lock(&pdr->lock);
> >       pdr->locator_init_complete = false;
> > -     mutex_unlock(&pdr->lock);
> >
> >       pdr->locator_addr.sq_node = 0;
> >       pdr->locator_addr.sq_port = 0;
> > +     mutex_unlock(&pdr->lock);
> >   }
> >
> >   static const struct qmi_ops pdr_locator_ops = {
> >
>
> These two functions are provided as qmi_ops handlers in pdr_locator_ops.
> Aren't they serialized in the qmi handle's workqueue since it as an
> ordered_workqueue? Even in a fast pdr scenario I don't think we would
> see a race condition between these two functions.
>
> The other access these two functions do race against is in the
> pdr_notifier_work. I think you would need to protect locator_addr in
> pdr_get_domain_list since the qmi_send_request there uses
> 'pdr->locator_addr'.

Thanks, I missed it initially. I think I'd keep the rest of the
changes and expand the lock to cover pdr_get_domain_list().

>
> Thanks!
> Chris



-- 
With best wishes
Dmitry

  reply	other threads:[~2024-05-11 21:52 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-24  9:27 [PATCH v7 0/6] soc: qcom: add in-kernel pd-mapper implementation Dmitry Baryshkov
2024-04-24  9:27 ` [PATCH v7 1/6] soc: qcom: pdr: protect locator_addr with the main mutex Dmitry Baryshkov
2024-04-25 19:30   ` Chris Lew
2024-05-11 21:52     ` Dmitry Baryshkov [this message]
2024-04-24  9:27 ` [PATCH v7 2/6] soc: qcom: pdr: fix parsing of domains lists Dmitry Baryshkov
2024-04-24  9:27 ` [PATCH v7 3/6] soc: qcom: pdr: extract PDR message marshalling data Dmitry Baryshkov
2024-04-24  9:28 ` [PATCH v7 4/6] soc: qcom: qmi: add a way to remove running service Dmitry Baryshkov
2024-04-25 20:57   ` Chris Lew
2024-04-24  9:28 ` [PATCH v7 5/6] soc: qcom: add pd-mapper implementation Dmitry Baryshkov
2024-04-26 13:48   ` Alexey Minnekhanov
2024-04-26 23:25   ` Chris Lew
2024-04-24  9:28 ` [PATCH v7 6/6] remoteproc: qcom: enable in-kernel PD mapper Dmitry Baryshkov
2024-04-27  1:03   ` Chris Lew
2024-04-27  1:36     ` Dmitry Baryshkov
2024-04-30 19:10       ` Chris Lew
2024-04-25  7:08 ` [PATCH v7 0/6] soc: qcom: add in-kernel pd-mapper implementation Steev Klimaszewski
2024-04-25  7:10   ` Dmitry Baryshkov
2024-04-26 14:02 ` Alexey Minnekhanov

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