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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 6B853C433FF for ; Mon, 12 Aug 2019 16:39:33 +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 3EA0A20679 for ; Mon, 12 Aug 2019 16:39:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Uo8bxcGd"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ti.com header.i=@ti.com header.b="PpzWiwYY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3EA0A20679 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=ti.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=lgSLFyqB3K8kAkicTX1HuF5wGblDEfZouVMEKHwCwe8=; b=Uo8bxcGd1viK5S pv5/1Qs/bsBjVtlhO/SW5go1IAGIicFGa+aoE3qtWtEuiiPVj7S7oVD+IIV1vV7luSNZOyePyCRir qYm2GzhJu1BNYjYT1cWx4A8StR8kJ5KMdI9pEBHcJuLAmNY97XdNj1fZJMRzzcPPwvVPtJBUtnZVd OEA0hzbAi48EgFkRi/WuvfTKdTJYa1dJhGSGY204KYm0qBUMMVvuLr+c+YTwgM8kph6YEDi6Z6Cc6 bx/YVCKMRGpT913H3Ak9ntQFgWcVBTcwx7MrnnGUKxfh6Xy6fSfHYjGMBgMx+kNTK/84fnbobb4qy ISQ5bArKZ06VCbo784Kw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hxDM4-0006zC-ME; Mon, 12 Aug 2019 16:39:32 +0000 Received: from lelv0143.ext.ti.com ([198.47.23.248]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hxDM2-0006ys-6O for linux-arm-kernel@lists.infradead.org; Mon, 12 Aug 2019 16:39:31 +0000 Received: from lelv0266.itg.ti.com ([10.180.67.225]) by lelv0143.ext.ti.com (8.15.2/8.15.2) with ESMTP id x7CGdSTf039298; Mon, 12 Aug 2019 11:39:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1565627968; bh=md23hPTLe4IPvI8vg4S3vMldyp9598RszV7otPnzrZs=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=PpzWiwYY+VyKSb9Mw62MGjQE/ijWqwxSpROIsNucd4bNrj8stlEeOcJYZSMxW6tGr SVRSCTTVoGjk7hG6NDU5UHrTgfIyJGdrz7KmezWkUwx8LxIDRGmqFL6V0PqpxE8kYT oPQJ4Owxz/UsmfTfAhooMptKdIblr+JAQgn2wdyM= Received: from DLEE113.ent.ti.com (dlee113.ent.ti.com [157.170.170.24]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id x7CGdSJc080163 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 12 Aug 2019 11:39:28 -0500 Received: from DLEE101.ent.ti.com (157.170.170.31) by DLEE113.ent.ti.com (157.170.170.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5; Mon, 12 Aug 2019 11:39:27 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE101.ent.ti.com (157.170.170.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5 via Frontend Transport; Mon, 12 Aug 2019 11:39:28 -0500 Received: from [128.247.58.153] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id x7CGdRfi108093; Mon, 12 Aug 2019 11:39:27 -0500 Subject: Re: [PATCH] rpmsg: virtio_rpmsg_bus: replace "%p" with "%pK" To: "Andrew F. Davis" , Bjorn Andersson References: <20181024011909.21674-1-s-anna@ti.com> <1cc3d697-6fde-901b-2e35-2e2b53b44425@ti.com> <2ef5e274-df09-c3a0-41ed-a945d1902eaf@ti.com> <92dc4403-8782-8dbf-b912-cc832ac748a7@ti.com> From: Suman Anna Message-ID: Date: Mon, 12 Aug 2019 11:39:27 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <92dc4403-8782-8dbf-b912-cc832ac748a7@ti.com> Content-Language: en-US X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190812_093930_320608_C16937A1 X-CRM114-Status: GOOD ( 17.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-kernel@lists.infradead.org, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, Loic Pallardy 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 8/12/19 11:36 AM, Andrew F. Davis wrote: > On 8/12/19 12:28 PM, Suman Anna wrote: >> On 8/12/19 10:47 AM, Andrew F. Davis wrote: >>> On 10/23/18 9:19 PM, Suman Anna wrote: >>>> The virtio_rpmsg_bus driver uses the "%p" format-specifier for >>>> printing the vring buffer address. This prints only a hashed >>>> pointer even for previliged users. Use "%pK" instead so that >>>> the address can be printed during debug using kptr_restrict >>>> sysctl. >>>> >>> >>> >>> s/previliged/privileged >> >> Bjorn, >> Can you fix this up when applying. >> >>> >>> You describe what the code does, but not why you need this. %pK is used >>> for only about 1% of pointer printing, why do you want to leak this >>> address to userspace at all? >> >> Andrew, >> Default behavior of %pK is same as %p, but it does allow you to control >> the print. The reason is clearly mentioned in the last sentence in the >> patch description. >> > > > Let me rephrase then, why would you ever set 'kptr_restrict' to anything > other than 0, or why do you want to be able to leak this address to > userspace at all? If the answer is just because you can, then all 12,000 > instances of %p in kernel could be converted for the same reason. It is a dev_dbg statement, so it is already under dynamic debug control. We would only ever use it during debug. regards Suman > > Andrew > > >> regards >> Suman >> >>> >>> Andrew >>> >>> >>>> Signed-off-by: Suman Anna >>>> --- >>>> drivers/rpmsg/virtio_rpmsg_bus.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c >>>> index f29dee731026..1345f373a1a0 100644 >>>> --- a/drivers/rpmsg/virtio_rpmsg_bus.c >>>> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c >>>> @@ -950,7 +950,7 @@ static int rpmsg_probe(struct virtio_device *vdev) >>>> goto vqs_del; >>>> } >>>> >>>> - dev_dbg(&vdev->dev, "buffers: va %p, dma %pad\n", >>>> + dev_dbg(&vdev->dev, "buffers: va %pK, dma %pad\n", >>>> bufs_va, &vrp->bufs_dma); >>>> >>>> /* half of the buffers is dedicated for RX */ >>>> >> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel