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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A7785C43603 for ; Fri, 13 Dec 2019 01:03:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5935F2073D for ; Fri, 13 Dec 2019 01:03:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="afuccXEW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5935F2073D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 42A128E0006; Thu, 12 Dec 2019 20:03:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4017C8E0001; Thu, 12 Dec 2019 20:03:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 33E658E0006; Thu, 12 Dec 2019 20:03:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0096.hostedemail.com [216.40.44.96]) by kanga.kvack.org (Postfix) with ESMTP id 1E5848E0001 for ; Thu, 12 Dec 2019 20:03:39 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id C6FD8181AEF1E for ; Fri, 13 Dec 2019 01:03:38 +0000 (UTC) X-FDA: 76258320516.29.dog82_2ac3745eab20 X-HE-Tag: dog82_2ac3745eab20 X-Filterd-Recvd-Size: 8833 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Fri, 13 Dec 2019 01:03:38 +0000 (UTC) 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 5FF082073D; Fri, 13 Dec 2019 01:03:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576199017; bh=7x7TUn5urpgUvMog1ds1wJw399j9cpRVWB8uT0RWdA8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=afuccXEWVW+zwaZj0kVO2PTbabSNO2UIpw64PtZjPZQleD/SXTRFtICfqXm84RY9b sT13bpbjURblJY+GZPaghSWsBzqmuHQA+8Km7uQqqHwETY2xabfATQDv6oaT6dfJNb kCMX/oMypUyhmRw6YTVwxQhX+OisOsdkTuZl/teQ= Date: Thu, 12 Dec 2019 17:03:36 -0800 From: Andrew Morton To: Dan Carpenter Cc: linux-mm@kvack.org, Daniel Axtens Subject: Re: [bug report] mm-add-apply_to_existing_pages-helper-fix Message-Id: <20191212170336.a8f7b29be837ec265126dd51@linux-foundation.org> In-Reply-To: <20191212092949.efpedkoshbehydfx@kili.mountain> References: <20191212092949.efpedkoshbehydfx@kili.mountain> 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 12 Dec 2019 12:29:49 +0300 Dan Carpenter wrote: > Hello Andrew Morton, > > The patch 3264ba9274f5: "mm-add-apply_to_existing_pages-helper-fix" > from Dec 11, 2019, leads to the following static checker warning: > > mm/memory.c:2166 __apply_to_page_range() > error: uninitialized symbol 'err'. > > mm/memory.c > 2144 static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, > 2145 unsigned long size, pte_fn_t fn, > 2146 void *data, bool create) > 2147 { > 2148 pgd_t *pgd; > 2149 unsigned long next; > 2150 unsigned long end = addr + size; > 2151 int err; > 2152 > 2153 if (WARN_ON(addr >= end)) > 2154 return -EINVAL; > 2155 > 2156 pgd = pgd_offset(mm, addr); > 2157 do { > 2158 next = pgd_addr_end(addr, end); > 2159 if (!create && pgd_none_or_clear_bad(pgd)) > 2160 continue; > ^^^^^^^^^ > It feels unlikely that we would always hit this continue but Smatch > complains. > Thanks. --- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix-fix-fix +++ a/mm/memory.c @@ -2148,7 +2148,7 @@ static int __apply_to_page_range(struct pgd_t *pgd; unsigned long next; unsigned long end = addr + size; - int err; + int err = 0; if (WARN_ON(addr >= end)) return -EINVAL; Daniel, have you had a chance to runtime test these various fiddles? From: Andrew Morton Subject: mm-add-apply_to_existing_pages-helper-fix reduce code duplication Cc: Daniel Axtens Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Qian Cai Cc: Uladzislau Rezki (Sony) Signed-off-by: Andrew Morton --- mm/memory.c | 43 +++++++++++++++++-------------------------- 1 file changed, 17 insertions(+), 26 deletions(-) --- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix +++ a/mm/memory.c @@ -2141,12 +2141,9 @@ static int apply_to_p4d_range(struct mm_ return err; } -/* - * Scan a region of virtual memory, filling in page tables as necessary - * and calling a provided function on each leaf page table. - */ -int apply_to_page_range(struct mm_struct *mm, unsigned long addr, - unsigned long size, pte_fn_t fn, void *data) +static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, + unsigned long size, pte_fn_t fn, + void *data, bool create) { pgd_t *pgd; unsigned long next; @@ -2159,13 +2156,25 @@ int apply_to_page_range(struct mm_struct pgd = pgd_offset(mm, addr); do { next = pgd_addr_end(addr, end); - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, true); + if (!create && pgd_none_or_clear_bad(pgd)) + continue; + err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create); if (err) break; } while (pgd++, addr = next, addr != end); return err; } + +/* + * Scan a region of virtual memory, filling in page tables as necessary + * and calling a provided function on each leaf page table. + */ +int apply_to_page_range(struct mm_struct *mm, unsigned long addr, + unsigned long size, pte_fn_t fn, void *data) +{ + return __apply_to_page_range(mm, addr, size, fn, data, true); +} EXPORT_SYMBOL_GPL(apply_to_page_range); /* @@ -2178,25 +2187,7 @@ EXPORT_SYMBOL_GPL(apply_to_page_range); int apply_to_existing_pages(struct mm_struct *mm, unsigned long addr, unsigned long size, pte_fn_t fn, void *data) { - pgd_t *pgd; - unsigned long next; - unsigned long end = addr + size; - int err = 0; - - if (WARN_ON(addr >= end)) - return -EINVAL; - - pgd = pgd_offset(mm, addr); - do { - next = pgd_addr_end(addr, end); - if (pgd_none_or_clear_bad(pgd)) - continue; - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, false); - if (err) - break; - } while (pgd++, addr = next, addr != end); - - return err; + return __apply_to_page_range(mm, addr, size, fn, data, false); } EXPORT_SYMBOL_GPL(apply_to_existing_pages); _ From: Andrew Morton Subject: mm-add-apply_to_existing_pages-helper-fix-fix s/apply_to_existing_pages/apply_to_existing_page_range/ Cc: Daniel Axtens Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Qian Cai Cc: Uladzislau Rezki (Sony) Signed-off-by: Andrew Morton --- include/linux/mm.h | 6 +++--- mm/memory.c | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) --- a/include/linux/mm.h~mm-add-apply_to_existing_pages-helper-fix-fix +++ a/include/linux/mm.h @@ -2621,9 +2621,9 @@ static inline int vm_fault_to_errno(vm_f typedef int (*pte_fn_t)(pte_t *pte, unsigned long addr, void *data); extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, pte_fn_t fn, void *data); -extern int apply_to_existing_pages(struct mm_struct *mm, unsigned long address, - unsigned long size, pte_fn_t fn, - void *data); +extern int apply_to_existing_page_range(struct mm_struct *mm, + unsigned long address, unsigned long size, + pte_fn_t fn, void *data); #ifdef CONFIG_PAGE_POISONING extern bool page_poisoning_enabled(void); --- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix-fix +++ a/mm/memory.c @@ -2184,12 +2184,12 @@ EXPORT_SYMBOL_GPL(apply_to_page_range); * Unlike apply_to_page_range, this does _not_ fill in page tables * where they are absent. */ -int apply_to_existing_pages(struct mm_struct *mm, unsigned long addr, - unsigned long size, pte_fn_t fn, void *data) +int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr, + unsigned long size, pte_fn_t fn, void *data) { return __apply_to_page_range(mm, addr, size, fn, data, false); } -EXPORT_SYMBOL_GPL(apply_to_existing_pages); +EXPORT_SYMBOL_GPL(apply_to_existing_page_range); /* * handle_pte_fault chooses page fault handler according to an entry which was _ From: Andrew Morton Subject: mm-add-apply_to_existing_pages-helper-fix-fix-fix initialize __apply_to_page_range::err Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Daniel Axtens Cc: Dmitry Vyukov Cc: Qian Cai Cc: Uladzislau Rezki (Sony) Signed-off-by: Andrew Morton --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix-fix-fix +++ a/mm/memory.c @@ -2148,7 +2148,7 @@ static int __apply_to_page_range(struct pgd_t *pgd; unsigned long next; unsigned long end = addr + size; - int err; + int err = 0; if (WARN_ON(addr >= end)) return -EINVAL; _