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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B927C43334 for ; Mon, 13 Jun 2022 10:33:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245499AbiFMKdE (ORCPT ); Mon, 13 Jun 2022 06:33:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346339AbiFMKa1 (ORCPT ); Mon, 13 Jun 2022 06:30:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 245591FA51; Mon, 13 Jun 2022 03:21:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6DCEE60AE8; Mon, 13 Jun 2022 10:21:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D628C34114; Mon, 13 Jun 2022 10:21:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655115673; bh=l3M5qn6Xz2e9y3Wi8sYO0gsFwQC5uBAZ1xUE9h4tvp0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mOCmNAzn9/0jKl2Lh39GElGKYdNVFM1owI+mMSAReP+FplQnPYCBXmah7NtfizMiI 2AUcUaCQflBjfe6Smoi92xoWgzNJDqNTfcWwg26xl0Pnq/tnJ0bmAm+26FjETIltXq PDMCTTSIJ0ose61prdwVULNSBBTeKr+lCliSabIg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xie Yongji , Fam Zheng , "Michael S. Tsirkin" , Jason Wang , Sasha Levin Subject: [PATCH 4.9 157/167] vringh: Fix loop descriptors check in the indirect cases Date: Mon, 13 Jun 2022 12:10:31 +0200 Message-Id: <20220613094917.736801133@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094840.720778945@linuxfoundation.org> References: <20220613094840.720778945@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xie Yongji [ Upstream commit dbd29e0752286af74243cf891accf472b2f3edd8 ] We should use size of descriptor chain to test loop condition in the indirect case. And another statistical count is also introduced for indirect descriptors to avoid conflict with the statistical count of direct descriptors. Fixes: f87d0fbb5798 ("vringh: host-side implementation of virtio rings.") Signed-off-by: Xie Yongji Signed-off-by: Fam Zheng Message-Id: <20220505100910.137-1-xieyongji@bytedance.com> Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Sasha Levin --- drivers/vhost/vringh.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index da47542496cc..63f0ab3e6f63 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -262,7 +262,7 @@ __vringh_iov(struct vringh *vrh, u16 i, gfp_t gfp, int (*copy)(void *dst, const void *src, size_t len)) { - int err, count = 0, up_next, desc_max; + int err, count = 0, indirect_count = 0, up_next, desc_max; struct vring_desc desc, *descs; struct vringh_range range = { -1ULL, 0 }, slowrange; bool slow = false; @@ -319,7 +319,12 @@ __vringh_iov(struct vringh *vrh, u16 i, continue; } - if (count++ == vrh->vring.num) { + if (up_next == -1) + count++; + else + indirect_count++; + + if (count > vrh->vring.num || indirect_count > desc_max) { vringh_bad("Descriptor loop in %p", descs); err = -ELOOP; goto fail; @@ -381,6 +386,7 @@ __vringh_iov(struct vringh *vrh, u16 i, i = return_from_indirect(vrh, &up_next, &descs, &desc_max); slow = false; + indirect_count = 0; } else break; } -- 2.35.1