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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 E25D4C5DF60 for ; Tue, 5 Nov 2019 17:46:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 85DC220663 for ; Tue, 5 Nov 2019 17:46:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="F5viLcZ7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85DC220663 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EEB856B0006; Tue, 5 Nov 2019 12:46:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E9C796B0007; Tue, 5 Nov 2019 12:46:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D8B156B0008; Tue, 5 Nov 2019 12:46:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0158.hostedemail.com [216.40.44.158]) by kanga.kvack.org (Postfix) with ESMTP id C0D376B0006 for ; Tue, 5 Nov 2019 12:46:30 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 7409345AA for ; Tue, 5 Nov 2019 17:46:30 +0000 (UTC) X-FDA: 76122953340.08.toad14_900f85b68094f X-HE-Tag: toad14_900f85b68094f X-Filterd-Recvd-Size: 3672 Received: from mail-il1-f170.google.com (mail-il1-f170.google.com [209.85.166.170]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Tue, 5 Nov 2019 17:46:29 +0000 (UTC) Received: by mail-il1-f170.google.com with SMTP id d83so19034866ilk.7 for ; Tue, 05 Nov 2019 09:46:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=l++MbLXneDnn87BTpCH+PemCtRkxraEOeDLFfiNrZII=; b=F5viLcZ7q3RlTf8kEAkGhf8g/cWugJIZuYHCm5u8eLkkgaNClRDUTcbFuu+cdo0TQ3 /wvg+EXEVyCgBjj9F0iAaLJUpHqiGw42KpCuxdOPy4mctBkJBnyEwt4eU6qH/f6WhRTn sk6tpCsjfqvfG9Qv0KKuDWB3Wzk4HzxLudKMhWC4nwcNlKVLzWf989yO69StFIC5j46B 4vq9AG8fVf07MJBKmbGyGR83M1yxdVu2JwlEhhVc0WbCg41TkcTZiSpryzuTG3o1oWd/ qWNC++9slbnLskxxljQtFda92ty37iStRTvk0xZ0/EAYcpcO2B9UXzOZ9qrwBrVZIyxF I46g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=l++MbLXneDnn87BTpCH+PemCtRkxraEOeDLFfiNrZII=; b=PYS4+r5oRQ98W81sqmIsMaOh2O2ODtAlq7cjNXBY4jyyYk7BdtsbvgzfSgbQZKGBL2 VEX8XqJfPf7O4stI2+osV6UjPK8elbZXvphmkXx4hjM1z8wjF6FxwCVO771UiiTzYf7k WI/4+LRaOOiv2n3MKkI5fuOc7k74eqV/Nq5W77WovfoY94q2Q/C3gzBqik70aqzaDW+X gzOi6qsbZgHY7W6oiLdKfqskleDhSNi2UAJEYI6P3k48ClCuzcuMTmgRNkIuR0WgIEDu /Gnlvr5z18RqfhfT/hYTV4allSnPBg6i4NFjRXkMZbHqBzR3hodCk4uFqj8XQMLykQ6F 2wGQ== X-Gm-Message-State: APjAAAUc6sdNUs+lv2h2LpIj7ys79vSxs7IXTSyV5GKHkUEnsSJlz1bc qTdCFvVO7KCJb7CTyKhXMBAxqB6FdrTCuss6T/5CeA== X-Google-Smtp-Source: APXvYqxHgvcG5koZvlufp9NVld0SaHrGSa3Tr7x/QR65ayRe/2aqU289UXSswpicAMzlZzqdA+nTGvO9teuWigOPNyw= X-Received: by 2002:a92:b60e:: with SMTP id s14mr19550411ili.178.1572975988906; Tue, 05 Nov 2019 09:46:28 -0800 (PST) MIME-Version: 1.0 References: <01cff98a-697e-c1b4-ddc2-9491347078a6@suse.cz> In-Reply-To: <01cff98a-697e-c1b4-ddc2-9491347078a6@suse.cz> From: Alex Zhang Date: Tue, 5 Nov 2019 09:46:12 -0800 Message-ID: Subject: Re: remap_pfn_range addr page alignment To: Vlastimil Babka Cc: linux-mm@kvack.org, Greg Thelen Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Ah yea, I was trying to do some device memory mapping where there's an offset into the page. Ok, I'll submit a patch that adds a VM_BUG_ON check that "addr" is page aligned and modify the header to reflect that. -Alex On Tue, Nov 5, 2019 at 8:04 AM Vlastimil Babka wrote: > > On 10/16/19 9:57 PM, Alex Zhang wrote: > > Hey there! > > > > I was seeing some weird behavior where I was hitting > > random BUG_ONs in memory.c . After a bit of debugging, > > I traced it back to remap_pfn_range being my entry point > > into memory.c . Should the "addr" passed it be page aligned? > > Most likely yes. How would you map if not on page boundary? I suspect it > was a bug in the caller? > > > I see no documentation stating that nor do I see any checks > > in the code for it. > > I suspect it was implicitly assumed. Most callers seem to pass > vma->vm_start as addr, which is page aligned. But 'size' parameter > alignment is fixed up, and it should be a similar case as addr. > Maybe a VM_BUG_ON check? > > > Alex > > > >