Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934700AbcLIQVo (ORCPT ); Fri, 9 Dec 2016 11:21:44 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:55756 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933393AbcLIQVl (ORCPT ); Fri, 9 Dec 2016 11:21:41 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Herbert Xu , Andrey Konovalov , "David S. Miller" Subject: [PATCH 4.8 18/45] netlink: Do not schedule work from sk_destruct Date: Fri, 9 Dec 2016 17:20:47 +0100 Message-Id: <20161209161755.670353642@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161209161754.912203877@linuxfoundation.org> References: <20161209161754.912203877@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2405 Lines: 87 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Herbert Xu [ Upstream commit ed5d7788a934a4b6d6d025e948ed4da496b4f12e ] It is wrong to schedule a work from sk_destruct using the socket as the memory reserve because the socket will be freed immediately after the return from sk_destruct. Instead we should do the deferral prior to sk_free. This patch does just that. Fixes: 707693c8a498 ("netlink: Call cb->done from a worker thread") Signed-off-by: Herbert Xu Tested-by: Andrey Konovalov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/netlink/af_netlink.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-) --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -322,11 +322,13 @@ static void netlink_skb_set_owner_r(stru sk_mem_charge(sk, skb->truesize); } -static void __netlink_sock_destruct(struct sock *sk) +static void netlink_sock_destruct(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); if (nlk->cb_running) { + if (nlk->cb.done) + nlk->cb.done(&nlk->cb); module_put(nlk->cb.module); kfree_skb(nlk->cb.skb); } @@ -348,21 +350,7 @@ static void netlink_sock_destruct_work(s struct netlink_sock *nlk = container_of(work, struct netlink_sock, work); - nlk->cb.done(&nlk->cb); - __netlink_sock_destruct(&nlk->sk); -} - -static void netlink_sock_destruct(struct sock *sk) -{ - struct netlink_sock *nlk = nlk_sk(sk); - - if (nlk->cb_running && nlk->cb.done) { - INIT_WORK(&nlk->work, netlink_sock_destruct_work); - schedule_work(&nlk->work); - return; - } - - __netlink_sock_destruct(sk); + sk_free(&nlk->sk); } /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on @@ -667,8 +655,18 @@ out_module: static void deferred_put_nlk_sk(struct rcu_head *head) { struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu); + struct sock *sk = &nlk->sk; + + if (!atomic_dec_and_test(&sk->sk_refcnt)) + return; + + if (nlk->cb_running && nlk->cb.done) { + INIT_WORK(&nlk->work, netlink_sock_destruct_work); + schedule_work(&nlk->work); + return; + } - sock_put(&nlk->sk); + sk_free(sk); } static int netlink_release(struct socket *sock)