On Sun, Mar 04, 2007 at 03:10:19PM +0100, Arnd Bergmann wrote:
> On Sunday 04 March 2007 14:38:12 Akinobu Mita wrote:
> > @@ -1168,8 +1168,10 @@ int configfs_register_subsystem(struct c
> >
> > err = -ENOMEM;
> > dentry = d_alloc(configfs_sb->s_root, &name);
> > - if (!dentry)
> > + if (!dentry) {
> > + mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
> > goto out_release;
> > + }
> >
> > d_add(dentry, NULL);
>
> This should be changed to jump to a new exit point, before the mutex_unlock
> at the end of the function. Having multiple places in the function that
> release the same lock easily leads to the kind of bug you are fixing here.
Agreed. Please see the patch below (untested).
Index: 2.6-mm/fs/configfs/dir.c
===================================================================
--- 2.6-mm.orig/fs/configfs/dir.c
+++ 2.6-mm/fs/configfs/dir.c
@@ -1169,25 +1169,26 @@ int configfs_register_subsystem(struct c
err = -ENOMEM;
dentry = d_alloc(configfs_sb->s_root, &name);
if (!dentry)
- goto out_release;
+ goto out_unlock;
d_add(dentry, NULL);
err = configfs_attach_group(sd->s_element, &group->cg_item,
dentry);
- if (!err)
- dentry = NULL;
- else
- d_delete(dentry);
+ if (err)
+ goto out_d_delete;
mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
- if (dentry) {
- dput(dentry);
-out_release:
- unlink_group(group);
- configfs_release_fs();
- }
+ return 0;
+
+out_d_delete:
+ d_delete(dentry);
+ dput(dentry);
+out_unlock:
+ mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
+ unlink_group(group);
+ configfs_release_fs();
return err;
}
-
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