From patchwork Fri Aug 23 22:17:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ralph Campbell X-Patchwork-Id: 11112409 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 923001709 for ; Fri, 23 Aug 2019 22:18:17 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 7A556233FD for ; Fri, 23 Aug 2019 22:18:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7A556233FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B8DFE6ED5C; Fri, 23 Aug 2019 22:18:12 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from hqemgate14.nvidia.com (hqemgate14.nvidia.com [216.228.121.143]) by gabe.freedesktop.org (Postfix) with ESMTPS id DF2606ED5C; Fri, 23 Aug 2019 22:18:11 +0000 (UTC) Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 23 Aug 2019 15:18:11 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Fri, 23 Aug 2019 15:18:11 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Fri, 23 Aug 2019 15:18:11 -0700 Received: from HQMAIL110.nvidia.com (172.18.146.15) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 23 Aug 2019 22:18:11 +0000 Received: from HQMAIL101.nvidia.com (172.20.187.10) by hqmail110.nvidia.com (172.18.146.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 23 Aug 2019 22:18:09 +0000 Received: from hqnvemgw01.nvidia.com (172.20.150.20) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Fri, 23 Aug 2019 22:18:09 +0000 Received: from rcampbell-dev.nvidia.com (Not Verified[10.110.48.66]) by hqnvemgw01.nvidia.com with Trustwave SEG (v7, 5, 8, 10121) id ; Fri, 23 Aug 2019 15:18:09 -0700 From: Ralph Campbell To: Subject: [PATCH 2/2] mm/hmm: hmm_range_fault() infinite loop Date: Fri, 23 Aug 2019 15:17:53 -0700 Message-ID: <20190823221753.2514-3-rcampbell@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190823221753.2514-1-rcampbell@nvidia.com> References: <20190823221753.2514-1-rcampbell@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1566598691; bh=H0xCNFTKe9KT+REMj7c8+VZLGl6bVqw61h/FiyncJWs=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=Py/+nEgUIjhIZbSu7cNxlYuXfEoZik6c6x3VzsIs38x5i57ELvn5JRlErcGl1DLSm OPm61FMKufS0D/REIhl99DbtgwiyufGaCiuLtD8EtwBjFC2UWBQZpe9L/R3XF+LaCc pQYGZc/IOqyS2G+1GlYqg8wySXYGft4IwgvkW/lneMjxIKzhvyBTvhGlLWRH96F7be Fjkol1850wsIJiuiZ2VkFIBG8mjuuMqEH9je3XnpBUdEIlN96xf1lgzs2F34kKu7gW AU8/C52wqkZa4aBqUpmIEWGA90tAL+iwPA08Ennyfoh6kGscOu2VY2sukBo6VVT5Uz 8g47hs3zUIkNw== X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ralph Campbell , nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Jason Gunthorpe , amd-gfx@lists.freedesktop.org, Andrew Morton , Christoph Hellwig Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Normally, callers to handle_mm_fault() are supposed to check the vma->vm_flags first. hmm_range_fault() checks for VM_READ but doesn't check for VM_WRITE if the caller requests a page to be faulted in with write permission (via the hmm_range.pfns[] value). If the vma is write protected, this can result in an infinite loop: hmm_range_fault() walk_page_range() ... hmm_vma_walk_hole() hmm_vma_walk_hole_() hmm_vma_do_fault() handle_mm_fault(FAULT_FLAG_WRITE) /* returns VM_FAULT_WRITE */ /* returns -EBUSY */ /* returns -EBUSY */ /* returns -EBUSY */ /* loops on -EBUSY and range->valid */ Prevent this by checking for vma->vm_flags & VM_WRITE before calling handle_mm_fault(). Signed-off-by: Ralph Campbell Reviewed-by: Jason Gunthorpe --- mm/hmm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/hmm.c b/mm/hmm.c index 29371485fe94..4882b83aeccb 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -292,6 +292,9 @@ static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, hmm_vma_walk->last = addr; i = (addr - range->start) >> PAGE_SHIFT; + if (write_fault && walk->vma && !(walk->vma->vm_flags & VM_WRITE)) + return -EPERM; + for (; addr < end; addr += PAGE_SIZE, i++) { pfns[i] = range->values[HMM_PFN_NONE]; if (fault || write_fault) {