From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] sctp: avoid list_del_init if it's freeing the memory right away Date: Tue, 07 Feb 2017 14:21:21 -0500 (EST) Message-ID: <20170207.142121.1027174926882132252.davem@davemloft.net> References: Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org, vyasevich@gmail.com, nhorman@tuxdriver.com To: marcelo.leitner@gmail.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:55414 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754912AbdBGTWN (ORCPT ); Tue, 7 Feb 2017 14:22:13 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: From: Marcelo Ricardo Leitner Date: Tue, 7 Feb 2017 17:03:21 -0200 > There is no reason to use list_del_init() in these places as we are > going to free/destroy the memory in a few lines below. > > Signed-off-by: Marcelo Ricardo Leitner > --- > net/sctp/associola.c | 14 ++++---------- > net/sctp/auth.c | 8 ++------ > net/sctp/chunk.c | 4 ++-- > net/sctp/outqueue.c | 14 +++++++------- > net/sctp/sm_make_chunk.c | 3 +-- > 5 files changed, 16 insertions(+), 27 deletions(-) > > diff --git a/net/sctp/associola.c b/net/sctp/associola.c > index e50dc6d7543fd6acfa7442f3a9ee575203c7718d..7eb9dacfa53a438b20a34319cf01c6c9a591f0c3 100644 > --- a/net/sctp/associola.c > +++ b/net/sctp/associola.c > @@ -1638,25 +1638,19 @@ int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp) > static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc) > { > struct sctp_chunk *asconf; > - struct sctp_chunk *tmp; > > - list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) { > - list_del_init(&asconf->list); > + list_for_each_entry(asconf, &asoc->addip_chunk_list, list) > sctp_chunk_free(asconf); > - } > } This leave freed memory on the asoc->addip_chunk_list, in fact why aren't you seeing the BUG_ON() in sctp_chunk_destroy() get triggered? If you elide the list_del() here then the "list_empty(&chunk->list)" check there will not be true. I don't think this transformation here is legal at all.