From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id DB84B6B008A for ; Mon, 20 Dec 2010 17:14:19 -0500 (EST) Date: Mon, 20 Dec 2010 23:05:25 +0100 (CET) From: Jesper Juhl Subject: Re: [updated PATCH] Close mem leak in error path in mm/hugetlb.c::nr_hugepages_store_common() In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323328-245131414-1292882725=:23785" Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton List-ID: This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323328-245131414-1292882725=:23785 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT On Mon, 20 Dec 2010, Minchan Kim wrote: > On Mon, Dec 20, 2010 at 7:10 AM, Jesper Juhl wrote: > > Hi, > > > > The NODEMASK_ALLOC macro dynamically allocates memory for its second > > argument ('nodes_allowed' in this context). > > In nr_hugepages_store_common() we may abort early if strict_strtoul() > > fails, but in that case we do not free the memory already allocated to > > 'nodes_allowed', causing a memory leak. > > This patch closes the leak by freeing the memory in the error path. > > > > > > Signed-off-by: Jesper Juhl > > --- > > hugetlb.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > compile tested only > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > index 8585524..9fdcc35 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -1439,8 +1439,10 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy, > > NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); > > > > err = strict_strtoul(buf, 10, &count); > > - if (err) > > + if (err) { > > + kfree(nodes_allowed); > > Nice catch. But use NODEMASK_FREE. It might be not kmalloced object. > Right. I just checked the macro and it used kmalloc(), so I just wrote kfree. But you are right, NODEMASK_FREE is the right thing to use here. Updated patch below. Signed-off-by: Jesper Juhl --- hugetlb.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 8585524..71e7886 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1439,8 +1439,10 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy, NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); err = strict_strtoul(buf, 10, &count); - if (err) + if (err) { + NODEMASK_FREE(nodes_allowed); return 0; + } h = kobj_to_hstate(kobj, &nid); if (nid == NUMA_NO_NODE) { -- Jesper Juhl http://www.chaosbits.net/ Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please. --8323328-245131414-1292882725=:23785-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org