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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 A3EF5C433E0 for ; Fri, 3 Jul 2020 19:04:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78B7A20724 for ; Fri, 3 Jul 2020 19:04:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593803079; bh=4pNuCfQIqgQH3q0qc1Q3ebM/lBgF6HLbGev3V+Gg3Iw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=Ev9xHf2UctFudrsQ6Gd2jjAKwkylGjXlK6Xj6co/O7HZYuK0DgfHOutfWtWr/iZbr 3O+hDTZSYEA4SD0caYUX0HWRTJkQz7fnJbii1yQgSZyAsRLxsxbL/V9wJaOWd0KEcd /Pn1kevl81ua0377sx1cwNhj5B2KHDARLucw2U9A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726710AbgGCTEi (ORCPT ); Fri, 3 Jul 2020 15:04:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:47252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726265AbgGCTEh (ORCPT ); Fri, 3 Jul 2020 15:04:37 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 47E8F20724; Fri, 3 Jul 2020 19:04:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593803077; bh=4pNuCfQIqgQH3q0qc1Q3ebM/lBgF6HLbGev3V+Gg3Iw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fGZzcO/5l+ihymtMX7ExVRl++j9zpGqwlnEhhHiQ7yQh/37hgSTJv4wfEMhdyfLqa YffdWJZcD+4yC9HaaDIv1j9KMSvKHAVfquU7AqjMPjmtmTIUL8nT3HyXHYSlmUBNzx CtsviZnp3/WcL3iIzm2yYrOT7U5wbqTo8kzkPu9o= Date: Fri, 3 Jul 2020 12:04:36 -0700 From: Andrew Morton To: trix@redhat.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm: initialize return of vm_insert_pages Message-Id: <20200703120436.4031b4ea23e28a3babca3d2d@linux-foundation.org> In-Reply-To: <20200703155354.29132-1-trix@redhat.com> References: <20200703155354.29132-1-trix@redhat.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 3 Jul 2020 08:53:54 -0700 trix@redhat.com wrote: > From: Tom Rix > > clang static analysis reports a garbage return > > In file included from mm/memory.c:84: > mm/memory.c:1612:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn] > return err; > ^~~~~~~~~~ > > The setting of err depends on a loop executing. > So initialize err. > > ... > > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1601,7 +1601,7 @@ int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr, > return insert_pages(vma, addr, pages, num, vma->vm_page_prot); > #else > unsigned long idx = 0, pgcount = *num; > - int err; > + int err = -EINVAL; > > for (; idx < pgcount; ++idx) { > err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]); If a caller were to ask vm_insert_pages() to insert zero pages, I suspect we should just return zero and set *num to zero.