From patchwork Tue Nov 21 22:43:06 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10069019 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 40C716022E for ; Tue, 21 Nov 2017 22:51:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2C33C29A6E for ; Tue, 21 Nov 2017 22:51:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 20AA229A79; Tue, 21 Nov 2017 22:51:23 +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=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D220629A6E for ; Tue, 21 Nov 2017 22:51:22 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 1977B2035BB3C; Tue, 21 Nov 2017 14:47:07 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=134.134.136.20; helo=mga02.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id D43F22035BB32 for ; Tue, 21 Nov 2017 14:47:05 -0800 (PST) Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Nov 2017 14:51:21 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,432,1505804400"; d="scan'208";a="151933699" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga004.jf.intel.com with ESMTP; 21 Nov 2017 14:51:21 -0800 Subject: [PATCH 2/2] device-dax: implement ->split() to catch invalid munmap attempts From: Dan Williams To: akpm@linux-foundation.org Date: Tue, 21 Nov 2017 14:43:06 -0800 Message-ID: <151130418681.4029.7118245855057952010.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <151130417573.4029.6745923267963684469.stgit@dwillia2-desk3.amr.corp.intel.com> References: <151130417573.4029.6745923267963684469.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, stable@vger.kernel.org, linux-nvdimm@lists.01.org Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Similar to how device-dax enforces that the 'address', 'offset', and 'len' parameters to mmap() be aligned to the device's fundamental alignment, the same constraints apply to munmap(). Implement ->split() to fail munmap calls that violate the alignment constraint. Otherwise, we later fail VM_BUG_ON checks in the unmap_page_range() path with crash signatures of the form: vma ffff8800b60c8a88 start 00007f88c0000000 end 00007f88c0e00000 next (null) prev (null) mm ffff8800b61150c0 prot 8000000000000027 anon_vma (null) vm_ops ffffffffa0091240 pgoff 0 file ffff8800b638ef80 private_data (null) flags: 0x380000fb(read|write|shared|mayread|maywrite|mayexec|mayshare|softdirty|mixedmap|hugepage) ------------[ cut here ]------------ kernel BUG at mm/huge_memory.c:2014! [..] RIP: 0010:__split_huge_pud+0x12a/0x180 [..] Call Trace: unmap_page_range+0x245/0xa40 ? __vma_adjust+0x301/0x990 unmap_vmas+0x4c/0xa0 unmap_region+0xae/0x120 ? __vma_rb_erase+0x11a/0x230 do_munmap+0x276/0x410 vm_munmap+0x6a/0xa0 SyS_munmap+0x1d/0x30 Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reported-by: Jeff Moyer Signed-off-by: Dan Williams --- drivers/dax/device.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 6833ada237ab..7b0bf825c4e7 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -428,9 +428,21 @@ static int dev_dax_fault(struct vm_fault *vmf) return dev_dax_huge_fault(vmf, PE_SIZE_PTE); } +static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr) +{ + struct file *filp = vma->vm_file; + struct dev_dax *dev_dax = filp->private_data; + struct dax_region *dax_region = dev_dax->region; + + if (!IS_ALIGNED(addr, dax_region->align)) + return -EINVAL; + return 0; +} + static const struct vm_operations_struct dax_vm_ops = { .fault = dev_dax_fault, .huge_fault = dev_dax_huge_fault, + .split = dev_dax_split, }; static int dax_mmap(struct file *filp, struct vm_area_struct *vma)