From 2b85146015525997ecba99b1530df26f581e970f Mon Sep 17 00:00:00 2001 From: Tim Gardner Date: Thu, 28 Aug 2014 11:26:03 -0600 Subject: [PATCH] fs: namespace: suppress 'may be used uninitialized' warnings MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 --- fs/compat.c | 10 ++++++---- fs/internal.h | 2 +- fs/namespace.c | 26 ++++++++------------------ 3 files changed, 15 insertions(+), 23 deletions(-) diff --git a/fs/compat.c b/fs/compat.c index 4bf082dbc273..4a03adb84f64 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -797,8 +797,9 @@ asmlinkage long compat_sys_mount(const char __user * dev_name, char *dir_page; 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_page = getname(dir_name); @@ -806,8 +807,9 @@ asmlinkage long compat_sys_mount(const char __user * dev_name, if (IS_ERR(dir_page)) 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); diff --git a/fs/internal.h b/fs/internal.h index fe327c20af83..03e1a1533d1c 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -60,7 +60,7 @@ extern int check_unsafe_exec(struct linux_binprm *); * 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 unsigned int mnt_get_count(struct vfsmount *mnt); extern struct vfsmount *__lookup_mnt(struct vfsmount *, struct dentry *, int); diff --git a/fs/namespace.c b/fs/namespace.c index 46f387704589..1f3503251487 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2254,21 +2254,9 @@ int copy_mount_options(const void __user * data, unsigned long *where) 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; } /* @@ -2536,8 +2524,9 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, 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); @@ -2546,8 +2535,9 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, 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); -- 2.30.2