From patchwork Mon Jun 15 04:01:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Yan X-Patchwork-Id: 11603757 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5BD0D6A2 for ; Mon, 15 Jun 2020 04:00:57 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id C140320768 for ; Mon, 15 Jun 2020 04:00:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C140320768 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18963-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 7721 invoked by uid 550); 15 Jun 2020 04:00:55 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 7671 invoked from network); 15 Jun 2020 04:00:51 -0000 From: Jason Yan To: , , , , CC: , Jason Yan , Kees Cook , Chao Yu Subject: [PATCH] erofs: Eliminate usage of uninitialized_var() macro Date: Mon, 15 Jun 2020 12:01:41 +0800 Message-ID: <20200615040141.3627746-1-yanaijie@huawei.com> X-Mailer: git-send-email 2.25.4 MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-CFilter-Loop: Reflected This is an effort to eliminate the uninitialized_var() macro[1]. The use of this macro is the wrong solution because it forces off ANY analysis by the compiler for a given variable. It even masks "unused variable" warnings. Quoted from Linus[2]: "It's a horrible thing to use, in that it adds extra cruft to the source code, and then shuts up a compiler warning (even the _reliable_ warnings from gcc)." The gcc option "-Wmaybe-uninitialized" has been disabled and this change will not produce any warnnings even with "make W=1". [1] https://github.com/KSPP/linux/issues/81 [2] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Cc: Kees Cook Cc: Chao Yu Signed-off-by: Jason Yan Reviewed-by: Chao Yu --- fs/erofs/data.c | 4 ++-- fs/erofs/zdata.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/erofs/data.c b/fs/erofs/data.c index 64b56c7df023..d0542151e8c4 100644 --- a/fs/erofs/data.c +++ b/fs/erofs/data.c @@ -265,7 +265,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio, */ static int erofs_raw_access_readpage(struct file *file, struct page *page) { - erofs_off_t uninitialized_var(last_block); + erofs_off_t last_block; struct bio *bio; trace_erofs_readpage(page, true); @@ -282,7 +282,7 @@ static int erofs_raw_access_readpage(struct file *file, struct page *page) static void erofs_raw_access_readahead(struct readahead_control *rac) { - erofs_off_t uninitialized_var(last_block); + erofs_off_t last_block; struct bio *bio = NULL; struct page *page; diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index be50a4d9d273..24a26aaf847f 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1161,7 +1161,7 @@ static void z_erofs_submit_queue(struct super_block *sb, struct z_erofs_decompressqueue *q[NR_JOBQUEUES]; void *bi_private; /* since bio will be NULL, no need to initialize last_index */ - pgoff_t uninitialized_var(last_index); + pgoff_t last_index; unsigned int nr_bios = 0; struct bio *bio = NULL;