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=-11.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 C5714C2D0A8 for ; Sat, 26 Sep 2020 07:16:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5405D206E5 for ; Sat, 26 Sep 2020 07:16:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="kOXkd8iQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726311AbgIZHQM (ORCPT ); Sat, 26 Sep 2020 03:16:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726037AbgIZHQL (ORCPT ); Sat, 26 Sep 2020 03:16:11 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE8FBC0613CE for ; Sat, 26 Sep 2020 00:16:11 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id l126so5217631pfd.5 for ; Sat, 26 Sep 2020 00:16:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=weak8dM0R5pKV3SDFvWdkknohBwvGyV0fCb3T4dKQi0=; b=kOXkd8iQRuYj4j1tGMK1mcdzOh+hgWyfv8vxRmTy6mPWOUiPxzvy0OWFnsoXI4k+ya ptobp8M8P+kyQysda/ouuBXOHJ1aXnnmpfzibI4afRfbQEaBgTC8RurVdC/46YmNRpfV ntcIFMPiiIdYPkXIRPAocbPhxdQTjIIsUa16eQUjZit7u5h9KSjS/spVo2rsyLsDPnyj rrPcrE6B01konwGmzZo0DWxNgDlAbCqY5gGU6SDTGb947VfOmN7PpE4jYkjY9lNKj3Q/ aY4yd3Ig26B9vX1CNWggIx8g6Ud4QVCxOuJajpiAW2jB2GTMN0us/d8Tkm/trNoP1act Henw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=weak8dM0R5pKV3SDFvWdkknohBwvGyV0fCb3T4dKQi0=; b=oAx7C2exkO6w/ous1NhpjYD2IEB7YtRR+xU1A0jQYE3+mji8sv2Tb6I/zC2tJ3Gaf/ 3trX0ChvBrtqxMgCzhKUATK1cehuBfbLgUKdc9/505Ao8AO6tevGEXKq8mn7RUQDVwtO l89WJAL2nC1NKMtq77xZPxhKU1zEAYb0ymnM86qBQcwpesp1ndH8tQh4VeC3NJhUjiBs mpqcJngcsOoNGYegf8BlL5AgkafEX7jovjz+yg0sXJAKEJxH2Z6wa/T27nXx6+GfH3S2 chaRaJ3613Wt3LVQiI5vkLoCcNdgLOCtFGVQEx1g49Ri7qixsQEmRzXwHM7FFxWYmiTQ CxTQ== X-Gm-Message-State: AOAM532DBLhe8WAhOthdNCQeUkJJP0BCNkccm6HP2o9x9t6OMDKDP8Vl NyuRYraKas+JlKftsddNAHht X-Google-Smtp-Source: ABdhPJyJ/P4qekNQ0ZtH1HhB3ONRmGpEwpbdqw2GUcK89yubMkc/QE3z8i0BaAvYaCgC2k4b8heFWQ== X-Received: by 2002:a63:4f17:: with SMTP id d23mr1921682pgb.319.1601104571177; Sat, 26 Sep 2020 00:16:11 -0700 (PDT) Received: from linux ([103.59.133.81]) by smtp.gmail.com with ESMTPSA id v128sm4256926pgv.72.2020.09.26.00.16.08 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sat, 26 Sep 2020 00:16:10 -0700 (PDT) Date: Sat, 26 Sep 2020 12:46:04 +0530 From: Manivannan Sadhasivam To: Greg KH Cc: Jeffrey Hugo , hemantk@codeaurora.org, bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] bus: mhi: core: debugfs: Use correct format specifiers for addresses Message-ID: <20200926071604.GC9302@linux> References: <20200925171608.30881-1-manivannan.sadhasivam@linaro.org> <20200926052742.GB9302@linux> <20200926053914.GA631346@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200926053914.GA631346@kroah.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Sat, Sep 26, 2020 at 07:39:14AM +0200, Greg KH wrote: > On Sat, Sep 26, 2020 at 10:57:42AM +0530, Manivannan Sadhasivam wrote: > > On Fri, Sep 25, 2020 at 12:01:54PM -0600, Jeffrey Hugo wrote: > > > On 9/25/2020 11:16 AM, Manivannan Sadhasivam wrote: > > > > For exposing the addresses of read/write pointers and doorbell register, > > > > let's use the correct format specifiers. This fixes the following issues > > > > generated using W=1 build in ARM32 and reported by Kbuild bot: > > > > > > > > All warnings (new ones prefixed by >>): > > > > > > > > > > drivers/bus/mhi/core/debugfs.c:75:7: warning: format specifies type 'unsigned long long' but the argument has type 'dma_addr_t' (aka 'unsigned int') [-Wformat] > > > > mhi_event->db_cfg.db_val); > > > > ^~~~~~~~~~~~~~~~~~~~~~~~ > > > > drivers/bus/mhi/core/debugfs.c:123:7: warning: format specifies type 'unsigned long long' but the argument has type 'dma_addr_t' (aka 'unsigned int') [-Wformat] > > > > mhi_chan->db_cfg.db_val); > > > > ^~~~~~~~~~~~~~~~~~~~~~~ > > > > 2 warnings generated. > > > > > > > > drivers/bus/mhi/core/debugfs.c: In function ‘mhi_debugfs_events_show’: > > > > drivers/bus/mhi/core/debugfs.c:74:51: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] > > > > seq_printf(m, " local rp: 0x%llx db: 0x%pad\n", (u64)ring->rp, > > > > ^ > > > > drivers/bus/mhi/core/debugfs.c: In function ‘mhi_debugfs_channels_show’: > > > > drivers/bus/mhi/core/debugfs.c:122:7: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] > > > > (u64)ring->rp, (u64)ring->wp, > > > > ^ > > > > drivers/bus/mhi/core/debugfs.c:122:22: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] > > > > (u64)ring->rp, (u64)ring->wp, > > > > ^ > > > > drivers/bus/mhi/core/debugfs.c:121:62: warning: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 5 has type ‘dma_addr_t {aka unsigned int}’ [-Wformat=] > > > > seq_printf(m, " local rp: 0x%llx local wp: 0x%llx db: 0x%llx\n", > > > > ~~~^ > > > > %x > > > > drivers/bus/mhi/core/debugfs.c:123:7: > > > > mhi_chan->db_cfg.db_val); > > > > > > > > Reported-by: kernel test robot > > > > Signed-off-by: Manivannan Sadhasivam > > > > --- > > > > > > > > Greg: This fixes the issue seen while testing the char-misc/char-misc-testing > > > > branch. > > > > > > > > drivers/bus/mhi/core/debugfs.c | 10 +++++----- > > > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/drivers/bus/mhi/core/debugfs.c b/drivers/bus/mhi/core/debugfs.c > > > > index 53d05a8e168d..2536ff92b76f 100644 > > > > --- a/drivers/bus/mhi/core/debugfs.c > > > > +++ b/drivers/bus/mhi/core/debugfs.c > > > > @@ -71,8 +71,8 @@ static int mhi_debugfs_events_show(struct seq_file *m, void *d) > > > > seq_printf(m, " rp: 0x%llx wp: 0x%llx", er_ctxt->rp, > > > > er_ctxt->wp); > > > > - seq_printf(m, " local rp: 0x%llx db: 0x%llx\n", (u64)ring->rp, > > > > - mhi_event->db_cfg.db_val); > > > > + seq_printf(m, " local rp: 0x%px db: 0x%pad\n", ring->rp, > > > > + &mhi_event->db_cfg.db_val); > > > > } > > > > return 0; > > > > @@ -118,9 +118,9 @@ static int mhi_debugfs_channels_show(struct seq_file *m, void *d) > > > > seq_printf(m, " base: 0x%llx len: 0x%llx wp: 0x%llx", > > > > chan_ctxt->rbase, chan_ctxt->rlen, chan_ctxt->wp); > > > > - seq_printf(m, " local rp: 0x%llx local wp: 0x%llx db: 0x%llx\n", > > > > - (u64)ring->rp, (u64)ring->wp, > > > > - mhi_chan->db_cfg.db_val); > > > > + seq_printf(m, " local rp: 0x%px local wp: 0x%px db: 0x%pad\n", > > > > + ring->rp, ring->wp, > > > > + &mhi_chan->db_cfg.db_val); > > > > } > > > > return 0; > > > > > > > > > > Documentation/printk-formats.txt seems to point out that %px is "insecure" > > > and thus perhaps not preferred. Are we assuming that debugfs is only > > > accessible by root, and thus the %px usage here is effectively the same as > > > %pK? > > > > > > > No, this debugfs entry can be read by non-root users also. > > How, the mount point of debugfs is restricted to root only :) > Sigh... I just went with the file permission of 444 :/ > > But the idea here > > is to effectively show the addresses to everyone so I don't think we need to > > hide it. The term "insecure" applies to kernel log where exposing the address > > doesn't make much sense (except for few obvious reasons). > > Why does normal users need to see a kernel address? What can they do > with this? Why can't we use the "normal" hashed way of showing a kernel > address instead? > It was the original implementation and as you brushed my memory, only root can mount and read the content, so why we should hide? Thanks, Mani > thanks, > > greg k-h