From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C12BBC43381 for ; Mon, 25 Mar 2019 11:55:27 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E2A9D20850 for ; Mon, 25 Mar 2019 11:55:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="q0J9tQsk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E2A9D20850 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JDps/bwb964LJvLJNENg8B3TzHJmH88XTnSwjxtwNTo=; b=q0J9tQskliExe6 k82xH0vgnNRQkT/mWV8d/3GrvvPs4l7mCh3m1gS+Fsa7xEWvSIsJ9xNLrRabnRkPp4VdBi7LDSNPy Ert7TTPQaBlLOLXj8+iHEzj5ulpzI87fKG5FV3uPnXcV4KWfqRpsp6HeOBLjatq82TYGMSKnIkH2F vOx7VRjjc1EeEzIuWv1bWTjHpxhkkz3nqZzsmXo2KQIbcHH8JVYatt8Y2TrIYYhTR5Eqw2dkiGK64 XVDh74RAHrawXJ1TmSPvOqcKkiT+uLhrVBzvyt85gDjYorKwyQjq5+frivqq/HR/j4GguHG1Zkhf6 vfEOCqRK8t7RfDB2g4XQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h8OCE-0007U7-2D; Mon, 25 Mar 2019 11:55:18 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h8OBx-0005zA-CT for linux-arm-kernel@lists.infradead.org; Mon, 25 Mar 2019 11:55:06 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ED09080D; Mon, 25 Mar 2019 04:55:00 -0700 (PDT) Received: from [10.1.196.69] (e112269-lin.cambridge.arm.com [10.1.196.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F30363F575; Mon, 25 Mar 2019 04:54:59 -0700 (PDT) Subject: Re: [PATCH] firmware: arm_scmi: check return value of idr_find To: Kangjie Lu References: <20190309040239.32431-1-kjlu@umn.edu> From: Steven Price Message-ID: <225abd6e-4551-213d-367b-93d938789188@arm.com> Date: Mon, 25 Mar 2019 11:54:58 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190309040239.32431-1-kjlu@umn.edu> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190325_045501_611024_A9DB2404 X-CRM114-Status: GOOD ( 19.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pakki001@umn.edu, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sudeep Holla Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 09/03/2019 04:02, Kangjie Lu wrote: > idr_find may return NULL, so check its return value and return an > error code. > > Signed-off-by: Kangjie Lu > --- > drivers/firmware/arm_scmi/driver.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c > index 8f952f2f1a29..35faa203d549 100644 > --- a/drivers/firmware/arm_scmi/driver.c > +++ b/drivers/firmware/arm_scmi/driver.c > @@ -709,6 +709,8 @@ scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id) > > if (scmi_mailbox_check(np)) { > cinfo = idr_find(&info->tx_idr, SCMI_PROTOCOL_BASE); > + if (!cinfo) > + return -EINVAL; > goto idr_alloc; > } > > I don't believe this situation can ever actually occur. The SCMI_PROTOCOL_BASE id is reserved just after the IDR is created in scmi_probe() in the first call to scmi_mbox_chan_setup(). That first call can't enter the above if() block because the scmi_mailbox_check() call has already been checked in scmi_probe(). It is only when processing the children in subsequent calls to scmi_mbox_chan_setup() that the check is on another node and so might fail. But by this time the SCMI_PROTOCOL_BASE id must exist. So there shouldn't be any way of reaching the situation where the IDR doesn't contain SCMI_PROTOCOL_BASE and idr_find() returns NULL. Having said that it did take me a while to understand the code well enough to reason that, and the above return should be handled appropriately, so you can add my Reviewed-by. But it would be worth expanding the commit message pointing out that there isn't actually a bug (yet). Steve _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel