Messages in this thread | | | Date | Mon, 12 Jun 2017 14:14:47 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH 02/11] kernfs: use idr instead of ida to manage inode number |
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Hello,
On Fri, Jun 02, 2017 at 02:53:55PM -0700, Shaohua Li wrote: > @@ -630,7 +633,11 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, > if (!kn) > goto err_out1; > > - ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL); > + idr_preload(GFP_KERNEL); > + spin_lock(&kernfs_idr_lock); > + ret = idr_alloc(&root->ino_idr, kn, 1, 0, GFP_ATOMIC); > + spin_unlock(&kernfs_idr_lock); > + idr_preload_end();
So, this ends up populating the idr w/ a kn which isn't fully initialized yet, which can lead to bugs which are difficult to hunt down as we're gonna allow kn's to be looked up through ino / gen. We probably should allocate with NULL here and populate the actual pointer with idr_replace() after the kn is fully initialized / online.
Thanks.
-- tejun
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