From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752027AbdDAN07 (ORCPT ); Sat, 1 Apr 2017 09:26:59 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36125 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751775AbdDANWh (ORCPT ); Sat, 1 Apr 2017 09:22:37 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Arnd Bergmann" , "Tim Gardner" , "Alexander Viro" Date: Sat, 01 Apr 2017 14:17:50 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 01/19] fs: namespace: suppress 'may be used uninitialized' warnings In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.43-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Tim Gardner commit b8850d1fa8e2f6653e57daf6d08e58c5f5eb2c85 upstream. The gcc version 4.9.1 compiler complains Even though it isn't possible for these variables to not get initialized before they are used. fs/namespace.c: In function ‘SyS_mount’: fs/namespace.c:2720:8: warning: ‘kernel_dev’ may be used uninitialized in this function [-Wmaybe-uninitialized] ret = do_mount(kernel_dev, kernel_dir->name, kernel_type, flags, ^ fs/namespace.c:2699:8: note: ‘kernel_dev’ was declared here char *kernel_dev; ^ fs/namespace.c:2720:8: warning: ‘kernel_type’ may be used uninitialized in this function [-Wmaybe-uninitialized] ret = do_mount(kernel_dev, kernel_dir->name, kernel_type, flags, ^ fs/namespace.c:2697:8: note: ‘kernel_type’ was declared here char *kernel_type; ^ Fix the warnings by simplifying copy_mount_string() as suggested by Al Viro. Cc: Alexander Viro Signed-off-by: Tim Gardner Signed-off-by: Al Viro Signed-off-by: Ben Hutchings Cc: Arnd Bergmann --- fs/compat.c | 10 ++++++---- fs/internal.h | 2 +- fs/namespace.c | 26 ++++++++------------------ 3 files changed, 15 insertions(+), 23 deletions(-) --- a/fs/compat.c +++ b/fs/compat.c @@ -797,8 +797,9 @@ COMPAT_SYSCALL_DEFINE5(mount, const char struct filename *dir; int retval; - retval = copy_mount_string(type, &kernel_type); - if (retval < 0) + kernel_type = copy_mount_string(type); + retval = PTR_ERR(kernel_type); + if (IS_ERR(kernel_type)) goto out; dir = getname(dir_name); @@ -806,8 +807,9 @@ COMPAT_SYSCALL_DEFINE5(mount, const char if (IS_ERR(dir)) goto out1; - retval = copy_mount_string(dev_name, &kernel_dev); - if (retval < 0) + kernel_dev = copy_mount_string(dev_name); + retval = PTR_ERR(kernel_dev); + if (IS_ERR(kernel_dev)) goto out2; retval = copy_mount_options(data, &data_page); --- a/fs/internal.h +++ b/fs/internal.h @@ -51,7 +51,7 @@ extern int vfs_path_lookup(struct dentry * namespace.c */ extern int copy_mount_options(const void __user *, unsigned long *); -extern int copy_mount_string(const void __user *, char **); +extern char *copy_mount_string(const void __user *); extern struct vfsmount *lookup_mnt(struct path *); extern int finish_automount(struct vfsmount *, struct path *); --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2482,21 +2482,9 @@ int copy_mount_options(const void __user return 0; } -int copy_mount_string(const void __user *data, char **where) +char *copy_mount_string(const void __user *data) { - char *tmp; - - if (!data) { - *where = NULL; - return 0; - } - - tmp = strndup_user(data, PAGE_SIZE); - if (IS_ERR(tmp)) - return PTR_ERR(tmp); - - *where = tmp; - return 0; + return data ? strndup_user(data, PAGE_SIZE) : NULL; } /* @@ -2766,8 +2754,9 @@ SYSCALL_DEFINE5(mount, char __user *, de char *kernel_dev; unsigned long data_page; - ret = copy_mount_string(type, &kernel_type); - if (ret < 0) + kernel_type = copy_mount_string(type); + ret = PTR_ERR(kernel_type); + if (IS_ERR(kernel_type)) goto out_type; kernel_dir = getname(dir_name); @@ -2776,8 +2765,9 @@ SYSCALL_DEFINE5(mount, char __user *, de goto out_dir; } - ret = copy_mount_string(dev_name, &kernel_dev); - if (ret < 0) + kernel_dev = copy_mount_string(dev_name); + ret = PTR_ERR(kernel_dev); + if (IS_ERR(kernel_dev)) goto out_dev; ret = copy_mount_options(data, &data_page);