Messages in this thread | | | Date | Thu, 25 Apr 2024 12:30:07 -0700 | Subject | Re: [PATCH v7 1/6] soc: qcom: pdr: protect locator_addr with the main mutex | From | Chris Lew <> |
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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! Chris
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