Re: linux-next: Tree for Jan 20 -- Kernel panic - Unable to mount root fs

Paul Walmsley
2015-01-21T21:54:37Z

On Wed, 21 Jan 2015, Al Viro wrote:

> Folks, could you check if the following on top of linux-next fixes the problem?

Tested-by: Paul Walmsley <paul@pwsan.com> # Tegra124 Jetson TK1

>
> diff --git a/fs/namei.c b/fs/namei.c
> index 323957f..cda89c3 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2056,13 +2056,22 @@ static int do_path_lookup(int dfd, const char *name,
> /* does lookup, returns the object with parent locked */
> struct dentry *kern_path_locked(const char *name, struct path *path)
> {
> + struct filename *filename = getname_kernel(name);
> struct nameidata nd;
> struct dentry *d;
> - int err = do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, &nd);
> - if (err)
> + int err;
> +
> + if (IS_ERR(filename))
> + return ERR_CAST(filename);
> +
> + err = filename_lookup(AT_FDCWD, filename, LOOKUP_PARENT, &nd);
> + if (err) {
> + putname(filename);
> return ERR_PTR(err);
> + }
> if (nd.last_type != LAST_NORM) {
> path_put(&nd.path);
> + putname(filename);
> return ERR_PTR(-EINVAL);
> }
> mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
> @@ -2070,9 +2079,11 @@ struct dentry *kern_path_locked(const char *name, struct path *path)
> if (IS_ERR(d)) {
> mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
> path_put(&nd.path);
> + putname(filename);
> return d;
> }
> *path = nd.path;
> + putname(filename);
> return d;
> }
>
> @@ -3314,7 +3325,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
> return file;
> }
>
> -struct dentry *kern_path_create(int dfd, const char *pathname,
> +static struct dentry *filename_create(int dfd, struct filename *name,
> struct path *path, unsigned int lookup_flags)
> {
> struct dentry *dentry = ERR_PTR(-EEXIST);
> @@ -3329,7 +3340,7 @@ struct dentry *kern_path_create(int dfd, const char *pathname,
> */
> lookup_flags &= LOOKUP_REVAL;
>
> - error = do_path_lookup(dfd, pathname, LOOKUP_PARENT|lookup_flags, &nd);
> + error = filename_lookup(dfd, name, LOOKUP_PARENT|lookup_flags, &nd);
> if (error)
> return ERR_PTR(error);
>
> @@ -3383,6 +3394,19 @@ out:
> path_put(&nd.path);
> return dentry;
> }
> +
> +struct dentry *kern_path_create(int dfd, const char *pathname,
> + struct path *path, unsigned int lookup_flags)
> +{
> + struct filename *filename = getname_kernel(pathname);
> + struct dentry *res = ERR_CAST(filename);
> +
> + if (!IS_ERR(filename)) {
> + res = filename_create(dfd, filename, path, lookup_flags);
> + putname(filename);
> + }
> + return res;
> +}
> EXPORT_SYMBOL(kern_path_create);
>
> void done_path_create(struct path *path, struct dentry *dentry)
> @@ -3401,7 +3425,7 @@ struct dentry *user_path_create(int dfd, const char __user *pathname,
> struct dentry *res;
> if (IS_ERR(tmp))
> return ERR_CAST(tmp);
> - res = kern_path_create(dfd, tmp->name, path, lookup_flags);
> + res = filename_create(dfd, tmp, path, lookup_flags);
> putname(tmp);
> return res;
> }
> --
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>

- Paul