From nobody Fri Dec 19 20:52:29 2025 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 492ACC38145 for ; Tue, 23 Aug 2022 10:17:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353780AbiHWKPy (ORCPT ); Tue, 23 Aug 2022 06:15:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352893AbiHWKG0 (ORCPT ); Tue, 23 Aug 2022 06:06:26 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37928A460; Tue, 23 Aug 2022 01:53:30 -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 93ACB611DD; Tue, 23 Aug 2022 08:53:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FCBCC433D6; Tue, 23 Aug 2022 08:53:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661244809; bh=WZrmzVPJBdBpw6UfrkbPuq4sZK3uUvd+tAu+0nNF+wo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TkjziN5ReaDaR45VxPUrCgobgl2VmDvTnjNNpj4KGTpJpPomhkDqjd1A3irXPMUXB QWRTQiBO7giSMftLoX+TQcukGJea6TbV4LqAv62sTLamss4oIOT9ArsEUHe039mHmh rkJxwv/9mtreEt48XlBzKW7W1vjBvnQWrKjRAsYM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Oleksandr Tyshchenko , Juergen Gross Subject: [PATCH 4.14 195/229] xen/xenbus: fix return type in xenbus_file_read() Date: Tue, 23 Aug 2022 10:25:56 +0200 Message-Id: <20220823080100.609879614@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080053.202747790@linuxfoundation.org> References: <20220823080053.202747790@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Dan Carpenter commit 32ad11127b95236dfc52375f3707853194a7f4b4 upstream. This code tries to store -EFAULT in an unsigned int. The xenbus_file_read() function returns type ssize_t so the negative value is returned as a positive value to the user. This change forces another change to the min() macro. Originally, the min() macro used "unsigned" type which checkpatch complains about. Also unsigned type would break if "len" were not capped at MAX_RW_COUNT. Use size_t for the min(). (No effect on runtime for the min_t() change). Fixes: 2fb3683e7b16 ("xen: Add xenbus device driver") Signed-off-by: Dan Carpenter Reviewed-by: Oleksandr Tyshchenko Link: https://lore.kernel.org/r/YutxJUaUYRG/VLVc@kili Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- drivers/xen/xenbus/xenbus_dev_frontend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/xen/xenbus/xenbus_dev_frontend.c +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c @@ -125,7 +125,7 @@ static ssize_t xenbus_file_read(struct f { struct xenbus_file_priv *u =3D filp->private_data; struct read_buffer *rb; - unsigned i; + ssize_t i; int ret; =20 mutex_lock(&u->reply_mutex); @@ -145,7 +145,7 @@ again: rb =3D list_entry(u->read_buffers.next, struct read_buffer, list); i =3D 0; while (i < len) { - unsigned sz =3D min((unsigned)len - i, rb->len - rb->cons); + size_t sz =3D min_t(size_t, len - i, rb->len - rb->cons); =20 ret =3D copy_to_user(ubuf + i, &rb->msg[rb->cons], sz);