From patchwork Tue Sep 1 15:07:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 310370 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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 224CBC433E2 for ; Tue, 1 Sep 2020 16:11:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA68C204EC for ; Tue, 1 Sep 2020 16:11:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598976668; bh=hFA+ejo3MW88ZO4xFBQQQLDRxo0rFnG78sbE4dwsNds=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZkKU9t9VC31q0eEF/3mggYhxlS7yQwvALSePxRhp+lenVDUhL1o3XF3zjRvFFoKKq Tqvy+V/txQX/xqzCWBUlhEMnbN0W79diEgSe+Jvozr4BFj7O+UmLmt0QageunaxUPn k45c31fy34dxG6PbpvQN4eTfCuqOYYtbjZhgc6Tw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728116AbgIAQLH (ORCPT ); Tue, 1 Sep 2020 12:11:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:46418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728849AbgIAPhz (ORCPT ); Tue, 1 Sep 2020 11:37:55 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B15BB20866; Tue, 1 Sep 2020 15:37:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598974675; bh=hFA+ejo3MW88ZO4xFBQQQLDRxo0rFnG78sbE4dwsNds=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qCa9gRjv8T/gQKWvES8dtHFKoRMwhjU7RQAoemQFy4PlI/uIhJHyXiYfet/8cYLL7 iIdv+vgHaJCKUGc0OIZrhHDvz0TiYuaAQtfSTpLfUKW0V0YIfTvwGfCpkkfi/R7yyp rknT+engezOrH+dFtP0PmySHQCohunOs4UUy2TzE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Prakash Gupta , Robin Murphy , Joerg Roedel , Sasha Levin Subject: [PATCH 5.8 021/255] iommu/iova: Dont BUG on invalid PFNs Date: Tue, 1 Sep 2020 17:07:57 +0200 Message-Id: <20200901151001.782764888@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901151000.800754757@linuxfoundation.org> References: <20200901151000.800754757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Robin Murphy [ Upstream commit d3e3d2be688b4b5864538de61e750721a311e4fc ] Unlike the other instances which represent a complete loss of consistency within the rcache mechanism itself, or a fundamental and obvious misconfiguration by an IOMMU driver, the BUG_ON() in iova_magazine_free_pfns() can be provoked at more or less any time in a "spooky action-at-a-distance" manner by any old device driver passing nonsense to dma_unmap_*() which then propagates through to queue_iova(). Not only is this well outside the IOVA layer's control, it's also nowhere near fatal enough to justify panicking anyway - all that really achieves is to make debugging the offending driver more difficult. Let's simply WARN and otherwise ignore bogus PFNs. Reported-by: Prakash Gupta Signed-off-by: Robin Murphy Reviewed-by: Prakash Gupta Link: https://lore.kernel.org/r/acbd2d092b42738a03a21b417ce64e27f8c91c86.1591103298.git.robin.murphy@arm.com Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/iova.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 49fc01f2a28d4..45a251da54537 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -811,7 +811,9 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad) for (i = 0 ; i < mag->size; ++i) { struct iova *iova = private_find_iova(iovad, mag->pfns[i]); - BUG_ON(!iova); + if (WARN_ON(!iova)) + continue; + private_free_iova(iovad, iova); }