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Wed, 04 Aug 2021 20:57:32 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mBNx9-007Qs2-Gr for linux-arm-kernel@lists.infradead.org; Wed, 04 Aug 2021 20:57:29 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4CC4C1FB; Wed, 4 Aug 2021 13:57:19 -0700 (PDT) Received: from e120937-lin (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4A34D3F40C; Wed, 4 Aug 2021 13:57:18 -0700 (PDT) Date: Wed, 4 Aug 2021 21:57:15 +0100 From: Cristian Marussi To: Rishabh Bhatnagar Cc: sudeep.holla@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, avajid@codeaurora.org, adharmap@codeaurora.org Subject: Re: [PATCH v2] firmware: arm_scmi: Free mailbox channels if probe fails Message-ID: <20210804205715.GT6592@e120937-lin> References: <1628099499-27394-1-git-send-email-rishabhb@codeaurora.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1628099499-27394-1-git-send-email-rishabhb@codeaurora.org> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210804_135727_697300_FFEDFD16 X-CRM114-Status: GOOD ( 28.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Aug 04, 2021 at 10:51:39AM -0700, Rishabh Bhatnagar wrote: > Mailbox channels for the base protocol are setup during probe. > There can be a scenario where probe fails to acquire the base > protocol due to a timeout leading to cleaning up of all device > managed memory including the scmi_mailbox structure setup during > mailbox_chan_setup function. > [ 12.735104]arm-scmi soc:qcom,scmi: timed out in resp(caller: version_get+0x84/0x140) > [ 12.735224]arm-scmi soc:qcom,scmi: unable to communicate with SCMI > [ 12.735947]arm-scmi: probe of soc:qcom,scmi failed with error -110 > > Now when a message arrives at cpu slightly after the timeout, the mailbox > controller will try to call the rx_callback of the client and might end > up accessing freed memory. > [ 12.758363][ C0] Call trace: > [ 12.758367][ C0] rx_callback+0x24/0x160 > [ 12.758372][ C0] mbox_chan_received_data+0x44/0x94 > [ 12.758386][ C0] __handle_irq_event_percpu+0xd4/0x240 > This patch frees the mailbox channels setup during probe and adds some more > error handling in case the probe fails. > > Signed-off-by: Rishabh Bhatnagar > --- Hi, > drivers/firmware/arm_scmi/driver.c | 35 ++++++++++++++++++++++++----------- > 1 file changed, 24 insertions(+), 11 deletions(-) > > diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c > index 9b2e8d4..aab2ac1 100644 > --- a/drivers/firmware/arm_scmi/driver.c > +++ b/drivers/firmware/arm_scmi/driver.c > @@ -1390,6 +1390,21 @@ void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table) > mutex_unlock(&scmi_requested_devices_mtx); > } > > +static int cleanup_txrx_channels(struct scmi_info *info) > +{ > + int ret; > + struct idr *idr = &info->tx_idr; > + > + ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > + idr_destroy(&info->tx_idr); > + > + idr = &info->rx_idr; > + ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > + idr_destroy(&info->rx_idr); > + > + return ret; > +} > + Sorry for being pedantic but the preferred naming for the function should be scmi_cleanup_txrx_channels() > static int scmi_probe(struct platform_device *pdev) > { > int ret; > @@ -1430,7 +1445,7 @@ static int scmi_probe(struct platform_device *pdev) > > ret = scmi_xfer_info_init(info); > if (ret) > - return ret; > + goto clear_txrx_setup; > > if (scmi_notification_init(handle)) > dev_err(dev, "SCMI Notifications NOT available.\n"); > @@ -1443,7 +1458,7 @@ static int scmi_probe(struct platform_device *pdev) > ret = scmi_protocol_acquire(handle, SCMI_PROTOCOL_BASE); > if (ret) { > dev_err(dev, "unable to communicate with SCMI\n"); > - return ret; > + goto notification_exit; > } > > mutex_lock(&scmi_list_mutex); > @@ -1482,6 +1497,12 @@ static int scmi_probe(struct platform_device *pdev) > } > > return 0; > + > +notification_exit: > + scmi_notification_exit(&info->handle); > +clear_txrx_setup: > + cleanup_txrx_channels(info); > + return ret; > } > > void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id) > @@ -1493,7 +1514,6 @@ static int scmi_remove(struct platform_device *pdev) > { > int ret = 0, id; > struct scmi_info *info = platform_get_drvdata(pdev); > - struct idr *idr = &info->tx_idr; > struct device_node *child; > > mutex_lock(&scmi_list_mutex); > @@ -1517,14 +1537,7 @@ static int scmi_remove(struct platform_device *pdev) > idr_destroy(&info->active_protocols); > > /* Safe to free channels since no more users */ > - ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > - idr_destroy(&info->tx_idr); > - > - idr = &info->rx_idr; > - ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > - idr_destroy(&info->rx_idr); > - > - return ret; > + return cleanup_txrx_channels(info); > } > Maybe also a Fixes: tag could be appropriate, but I'm not so sure you could easily identify one common commit to use given that notifications have been added later and the code around scmi_protocol_acquire() has been changed recently too. (in such a case just ignore the Fixes tag suggestion) Other than the above remarks, Reviewed-by: Cristian Marussi Thanks, Cristian _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel