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Commit b8850d1f authored by Tim Gardner's avatar Tim Gardner Committed by Al Viro
Browse files

fs: namespace: suppress 'may be used uninitialized' warnings 



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 <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8ba7f6c2

fs/compat.c

+6 −4
Original line number Diff line number Diff line
@@ -797,8 +797,9 @@ COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name, 
	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 __user *, dev_name, 
	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);

fs/internal.h

+1 −1
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *, 
 * 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 *);

fs/namespace.c

+8 −18
Original line number Diff line number Diff line
@@ -2514,21 +2514,9 @@ 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;

}



/*
@@ -2794,8 +2782,9 @@ 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);
@@ -2804,8 +2793,9 @@ 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);