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Wed, 4 Aug 2021 17:29:29 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: rishabhb) by smtp.codeaurora.org (Postfix) with ESMTPSA id 6913CC433F1; Wed, 4 Aug 2021 17:29:28 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 04 Aug 2021 10:29:28 -0700 From: rishabhb@codeaurora.org To: Cristian Marussi 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] firmware: arm_scmi: Free mailbox channels if probe fails In-Reply-To: <20210804084032.GS6592@e120937-lin> References: <1628029342-3638-1-git-send-email-rishabhb@codeaurora.org> <20210804083358.GR6592@e120937-lin> <20210804084032.GS6592@e120937-lin> Message-ID: <8b5434c123c2e310d7dbeac8c9a10146@codeaurora.org> X-Sender: rishabhb@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-08-04 01:40, Cristian Marussi wrote: > On Wed, Aug 04, 2021 at 09:33:58AM +0100, Cristian Marussi wrote: >> On Tue, Aug 03, 2021 at 03:22:22PM -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. >> > >> > Change-Id: I1214ec2c4c92c4a3ca5fa73de11e0e403b13b46a >> > Signed-off-by: Rishabh Bhatnagar >> >> Hi Rishabh, >> >> Good catch, thanks for this. >> > > Hi again, > > sorry forgot one thing. > >> > --- >> > drivers/firmware/arm_scmi/driver.c | 11 +++++++++-- >> > 1 file changed, 9 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c >> > index 9b2e8d4..518c7b9 100644 >> > --- a/drivers/firmware/arm_scmi/driver.c >> > +++ b/drivers/firmware/arm_scmi/driver.c >> > @@ -1430,7 +1430,7 @@ 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 +1443,7 @@ 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 +1482,13 @@ static int scmi_probe(struct platform_device *pdev) >> > } >> > >> > return 0; >> > + >> > +notification_exit: >> > + scmi_notification_exit(&info->handle); >> > +clear_txrx_setup: >> > + idr_for_each(&info->tx_idr, info->desc->ops->chan_free, &info->tx_idr); >> > + idr_for_each(&info->rx_idr, info->desc->ops->chan_free, &info->rx_idr); >> > + return ret; >> > } >> > >> >> Shouldn't we also clear the internal IDRs memory allocs after these >> idr_for_each() adding a couple of: >> >> idr_destroy(&info->tx_idr); >> >> idr_destroy(&info->rx_idr); >> >> like scmi_remove() does ? >> > > Maybe it could be worth at this point unifying this common > "cleanup-all-channels" > logic shared between scmi_probe()-error-path and scmi_remove() into its > own > helper function to call from both sites. > > Thanks, > Cristian Thanks for the review. I'll move the cleanup to a common helper function. It makes sense to destroy tx/rx idrs. I didn't realize they allocate memory internally.