From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938805AbdEYSy2 (ORCPT ); Thu, 25 May 2017 14:54:28 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:36718 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1036419AbdEYSvb (ORCPT ); Thu, 25 May 2017 14:51:31 -0400 From: Manfred Spraul To: mtk.manpages@gmail.com, Andrew Morton , Kees Cook Cc: LKML , 1vier1@web.de, Davidlohr Bueso , mingo@kernel.org, peterz@infradead.org, fabf@skynet.be, Manfred Spraul Subject: [PATCH 13/20] ipc/sem.c: Avoid ipc_rcu_putref for failed ipc_addid() Date: Thu, 25 May 2017 20:51:00 +0200 Message-Id: <20170525185107.12869-14-manfred@colorfullife.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170525185107.12869-1-manfred@colorfullife.com> References: <20170508222345.GA52073@beast> <20170525185107.12869-1-manfred@colorfullife.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Loosely based on a patch from Kees Cook : - id and retval can be merged - if ipc_addid() fails, then use call_rcu() directly. The difference is that call_rcu is used for failed ipc_addid() calls, to continue to guaranteed an rcu delay for security_sem_free(). Signed-off-by: Manfred Spraul Cc: Kees Cook --- ipc/sem.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/ipc/sem.c b/ipc/sem.c index 445a5b5..2b2ed56 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -479,7 +479,6 @@ static struct sem_array *sem_alloc(size_t nsems) */ static int newary(struct ipc_namespace *ns, struct ipc_params *params) { - int id; int retval; struct sem_array *sma; key_t key = params->key; @@ -520,10 +519,10 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) sma->sem_nsems = nsems; sma->sem_ctime = get_seconds(); - id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); - if (id < 0) { - ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); - return id; + retval = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); + if (retval < 0) { + call_rcu(&sma->sem_perm.rcu, sem_rcu_free); + return retval; } ns->used_sems += nsems; -- 2.9.3