From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761680Ab3JPRxS (ORCPT ); Wed, 16 Oct 2013 13:53:18 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35955 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934641Ab3JPRqd (ORCPT ); Wed, 16 Oct 2013 13:46:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Davidlohr Bueso , Sedat Dilek , Rik van Riel , Manfred Spraul , Andrew Morton , Linus Torvalds , Mike Galbraith Subject: [ 35/50] ipc,shm: introduce shmctl_nolock Date: Wed, 16 Oct 2013 10:45:21 -0700 Message-Id: <20131016174402.618737988@linuxfoundation.org> X-Mailer: git-send-email 1.8.4.3.gca3854a In-Reply-To: <20131016174358.335646140@linuxfoundation.org> References: <20131016174358.335646140@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davidlohr Bueso commit 68eccc1dc345539d589ae78ee43b835c1a06a134 upstream. Similar to semctl and msgctl, when calling msgctl, the *_INFO and *_STAT commands can be performed without acquiring the ipc object. Add a shmctl_nolock() function and move the logic of *_INFO and *_STAT out of msgctl(). Since we are just moving functionality, this change still takes the lock and it will be properly lockless in the next patch. Signed-off-by: Davidlohr Bueso Tested-by: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman --- ipc/shm.c | 57 +++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 39 insertions(+), 18 deletions(-) --- a/ipc/shm.c +++ b/ipc/shm.c @@ -827,29 +827,24 @@ out_up: return err; } -SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +static int shmctl_nolock(struct ipc_namespace *ns, int shmid, + int cmd, int version, void __user *buf) { + int err; struct shmid_kernel *shp; - int err, version; - struct ipc_namespace *ns; - if (cmd < 0 || shmid < 0) { - err = -EINVAL; - goto out; + /* preliminary security checks for *_INFO */ + if (cmd == IPC_INFO || cmd == SHM_INFO) { + err = security_shm_shmctl(NULL, cmd); + if (err) + return err; } - version = ipc_parse_version(&cmd); - ns = current->nsproxy->ipc_ns; - - switch (cmd) { /* replace with proc interface ? */ + switch (cmd) { case IPC_INFO: { struct shminfo64 shminfo; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shminfo, 0, sizeof(shminfo)); shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; shminfo.shmmax = ns->shm_ctlmax; @@ -871,10 +866,6 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, { struct shm_info shm_info; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shm_info, 0, sizeof(shm_info)); down_read(&shm_ids(ns).rw_mutex); shm_info.used_ids = shm_ids(ns).in_use; @@ -935,6 +926,36 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, err = result; goto out; } + default: + return -EINVAL; + } + +out_unlock: + shm_unlock(shp); +out: + return err; +} + +SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +{ + struct shmid_kernel *shp; + int err, version; + struct ipc_namespace *ns; + + if (cmd < 0 || shmid < 0) { + err = -EINVAL; + goto out; + } + + version = ipc_parse_version(&cmd); + ns = current->nsproxy->ipc_ns; + + switch (cmd) { + case IPC_INFO: + case SHM_INFO: + case SHM_STAT: + case IPC_STAT: + return shmctl_nolock(ns, shmid, cmd, version, buf); case SHM_LOCK: case SHM_UNLOCK: {