From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) by kanga.kvack.org (Postfix) with ESMTP id CD6866B30BF for ; Fri, 23 Nov 2018 05:37:59 -0500 (EST) Received: by mail-qt1-f197.google.com with SMTP id n50so8463389qtb.9 for ; Fri, 23 Nov 2018 02:37:59 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id w64si7386600qte.374.2018.11.23.02.37.58 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Nov 2018 02:37:59 -0800 (PST) Subject: Re: [PATCH] mm: debug: Fix a width vs precision bug in printk References: <20181123072135.gqvblm2vdujbvfjs@kili.mountain> From: David Hildenbrand Message-ID: <831d66e9-7cf7-00a5-0a40-b7a7109dddbf@redhat.com> Date: Fri, 23 Nov 2018 11:37:55 +0100 MIME-Version: 1.0 In-Reply-To: <20181123072135.gqvblm2vdujbvfjs@kili.mountain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dan Carpenter , Andrew Morton , Michal Hocko Cc: Pavel Tatashin , Alexander Duyck , Matthew Wilcox , linux-mm@kvack.org, kernel-janitors@vger.kernel.org On 23.11.18 08:21, Dan Carpenter wrote: > We had intended to only print dentry->d_name.len characters but there is > a width vs precision typo so if the name isn't NUL terminated it will > read past the end of the buffer. > > Fixes: 408ddbc22be3 ("mm: print more information about mapping in __dump_page") > Signed-off-by: Dan Carpenter > --- > mm/debug.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/debug.c b/mm/debug.c > index d18c5cea3320..faf856b652b6 100644 > --- a/mm/debug.c > +++ b/mm/debug.c > @@ -80,7 +80,7 @@ void __dump_page(struct page *page, const char *reason) > if (mapping->host->i_dentry.first) { > struct dentry *dentry; > dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias); > - pr_warn("name:\"%*s\" ", dentry->d_name.len, dentry->d_name.name); > + pr_warn("name:\"%.*s\" ", dentry->d_name.len, dentry->d_name.name); > } > } > BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); > Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb