From patchwork Tue Jul 30 18:34:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Souptick Joarder X-Patchwork-Id: 11066489 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 89B1314DB for ; Tue, 30 Jul 2019 18:32:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 81836285E0 for ; Tue, 30 Jul 2019 18:32:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 74ABE28830; Tue, 30 Jul 2019 18:32:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F2A16285E0 for ; Tue, 30 Jul 2019 18:32:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B059B8E0003; Tue, 30 Jul 2019 14:32:50 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id AB6FB8E0001; Tue, 30 Jul 2019 14:32:50 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9A5DC8E0003; Tue, 30 Jul 2019 14:32:50 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by kanga.kvack.org (Postfix) with ESMTP id 64DBA8E0001 for ; Tue, 30 Jul 2019 14:32:50 -0400 (EDT) Received: by mail-pl1-f197.google.com with SMTP id y9so35834618plp.12 for ; Tue, 30 Jul 2019 11:32:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:from:to:cc:subject:date :message-id:mime-version:content-transfer-encoding; bh=6fCIBt83Qg0xm9/csFeyeLFWARKqAMvTELcBmphTpo0=; b=mSxpDZ05qQr87UsOdnhCVswEpoF8Q7XWTtAQApIJtpwvqZWmAOUgbjtYwnWKnDKz1t 65WZ5zsZEWlWN894VJ5IxFkIJSoyErSFsdY/eGMIqUh6e//xXT7QCkVsm3vCbItcvxC8 qnmgoslaCDY5sjMAqqn5M7jJGsd82og5os1F93eEIIv7DR5uzGJ0kDIUz+Ul/C/qmB+z oi9LhIVvOun6rPabRr9QAXgOXUB5Vi2ylxZ7JQd3PyZYnKmkqBDG6bLvAXQyFADz/6PM 99zjxx9nqOs+vIgmELPlvp/VmjhaWHRH265fr8M3ZCKD3Y+7JvmYskxQ6WzKLPAgZzG8 9mew== X-Gm-Message-State: APjAAAWmxf1lHa6/9A8c3dX9w7XO6uPXQUeIRg0IqcAhj8XA8TpIB9pD jjFfdlisenhUqpPK2/3cn6Vx5+cZdmHXo97ge8cn7+tPRwvCyA8gDBWHLkumK04EulQNYYf5rSJ TG5ZG1AP4GcngbJ+2AomYX5jEuk5aFoReQIaTv9Q58pmHWsbVo1wSkoJynuveXMAPeQ== X-Received: by 2002:a17:902:aa83:: with SMTP id d3mr113003944plr.74.1564511569918; Tue, 30 Jul 2019 11:32:49 -0700 (PDT) X-Received: by 2002:a17:902:aa83:: with SMTP id d3mr113003891plr.74.1564511569060; Tue, 30 Jul 2019 11:32:49 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1564511569; cv=none; d=google.com; s=arc-20160816; b=RNScVMncVneQgs5A/4Jpt2N7mrZr8+5pLsCdTdjRFD8ZGHMNsnQmt5Q3A8DERm2dov j46z8r3HFoGFHwnDDVTze6OCc1nwm1eEcTsJe2MTzIoh238oL2sjxNsFLa+tZ6BDrdX6 KcS7rZzbKGmOLgoCS0T6Z01HGvk7bsX/z2DhK1V82ZrqZivw+3pRRYDnbLPhBXth4cD0 mTBk/rVYL1UqGXORItAgj61mRuqPirk9jTNXMggcqsxQAiKnWtf4+TycckGG0zvgWakQ S3+PYgib4isXddd12VCHcqzyNLc2nkUhYeIdJZkJovoK5Xi3VUFzjRL9XrtKED6QSIJQ BLhw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:dkim-signature; bh=6fCIBt83Qg0xm9/csFeyeLFWARKqAMvTELcBmphTpo0=; b=oeoTaD2GHUrhBmOjAWkiFb+BPjeBe/fWoUAvGmin3Sj1rMzoGCKmzPrVTPai10e8cQ dNuTltlDOqnVZ/AWiH2HI/AhsEHOjuCAs4hrSewPe7UeEVvIVneYWKPnHVqIUIhCb95E g2pYIyZpS/szJpmIS1Pp24a0rkPUGi4JdG1oWLaXuS3KcxTxakhrnFQA8BbEWOcJw7TJ 3HEm6bnI6eRIIANOWJkKmwnOSJLWFWkW1VpUysmgI/ZRfCENUTENls8ZYjJyi7hVQiiJ gZ5ixc5UfFNZDxiHWQ/8l0yLcWJBE6Sm3WJqpsiFpfQ/dGJNg46LYzdgKHoEBFJxiLy3 gxRA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=JUA9FbUP; spf=pass (google.com: domain of jrdr.linux@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=jrdr.linux@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id n6sor47056200pfq.67.2019.07.30.11.32.48 for (Google Transport Security); Tue, 30 Jul 2019 11:32:49 -0700 (PDT) Received-SPF: pass (google.com: domain of jrdr.linux@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=JUA9FbUP; spf=pass (google.com: domain of jrdr.linux@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=jrdr.linux@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=6fCIBt83Qg0xm9/csFeyeLFWARKqAMvTELcBmphTpo0=; b=JUA9FbUPr0F6xNgBd5J9MHwHtCHrMpBJuNDTvZBzKBZeCmNsbohHado2HBbGTi0It9 yThD+OL5Bkf6Da9wJnEKF7n1ZuYfE+RCaAChBqmkI/jmB2QhloDai+ucTPidoKT2u6UQ 29UC6QoAyrEf4tN2GNQniwXjZkr83rJH4ak6SFrbJFSb15jmyMBIWZiHh1EgvVH6j48q cZKmuIlqPfwxsnRzt4ye0SXQ2NpyGAmqO03R0RsRzNRYkzGXP/3U1W6hIGXqsFMnjHXR g7Xo3I2gA+uPgrVqyPZw3rp948eNJFIjP60aR0GcG/CsRV9BR7dafhIdCpB5PUi2sogn ixHw== X-Google-Smtp-Source: APXvYqz3TKO5CR8bm9L/zAhw0K/5mmOOXYnkeug29AHRYcKaRz4UPuCN4Qa7WYzWXEa+PlUkZGXEBw== X-Received: by 2002:a62:754d:: with SMTP id q74mr42050335pfc.211.1564511568653; Tue, 30 Jul 2019 11:32:48 -0700 (PDT) Received: from jordon-HP-15-Notebook-PC.domain.name ([106.51.16.0]) by smtp.gmail.com with ESMTPSA id j5sm57328671pgp.59.2019.07.30.11.32.43 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 30 Jul 2019 11:32:47 -0700 (PDT) From: Souptick Joarder To: boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org, marmarek@invisiblethingslab.com Cc: willy@infradead.org, akpm@linux-foundation.org, linux@armlinux.org.uk, linux-mm@kvack.org, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, gregkh@linuxfoundation.org, Souptick Joarder Subject: [PATCH] xen/gntdev.c: Replace vm_map_pages() with vm_map_pages_zero() Date: Wed, 31 Jul 2019 00:04:56 +0530 Message-Id: <1564511696-4044-1-git-send-email-jrdr.linux@gmail.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 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: X-Virus-Scanned: ClamAV using ClamSMTP 'commit df9bde015a72 ("xen/gntdev.c: convert to use vm_map_pages()")' breaks gntdev driver. If vma->vm_pgoff > 0, vm_map_pages() will: - use map->pages starting at vma->vm_pgoff instead of 0 - verify map->count against vma_pages()+vma->vm_pgoff instead of just vma_pages(). In practice, this breaks using a single gntdev FD for mapping multiple grants. relevant strace output: [pid 857] ioctl(7, IOCTL_GNTDEV_MAP_GRANT_REF, 0x7ffd3407b6d0) = 0 [pid 857] mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, 7, 0) = 0x777f1211b000 [pid 857] ioctl(7, IOCTL_GNTDEV_SET_UNMAP_NOTIFY, 0x7ffd3407b710) = 0 [pid 857] ioctl(7, IOCTL_GNTDEV_MAP_GRANT_REF, 0x7ffd3407b6d0) = 0 [pid 857] mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, 7, 0x1000) = -1 ENXIO (No such device or address) details here: https://github.com/QubesOS/qubes-issues/issues/5199 The reason is -> ( copying Marek's word from discussion) vma->vm_pgoff is used as index passed to gntdev_find_map_index. It's basically using this parameter for "which grant reference to map". map struct returned by gntdev_find_map_index() describes just the pages to be mapped. Specifically map->pages[0] should be mapped at vma->vm_start, not vma->vm_start+vma->vm_pgoff*PAGE_SIZE. When trying to map grant with index (aka vma->vm_pgoff) > 1, __vm_map_pages() will refuse to map it because it will expect map->count to be at least vma_pages(vma)+vma->vm_pgoff, while it is exactly vma_pages(vma). Converting vm_map_pages() to use vm_map_pages_zero() will fix the problem. Marek has tested and confirmed the same. Reported-by: Marek Marczykowski-Górecki Signed-off-by: Souptick Joarder Tested-by: Marek Marczykowski-Górecki Reviewed-by: Boris Ostrovsky --- drivers/xen/gntdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 4c339c7..a446a72 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -1143,7 +1143,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) goto out_put_map; if (!use_ptemod) { - err = vm_map_pages(vma, map->pages, map->count); + err = vm_map_pages_zero(vma, map->pages, map->count); if (err) goto out_put_map; } else {