Messages in this thread | | | Date | Wed, 22 Jun 2016 17:46:12 +0100 | From | Al Viro <> | Subject | Re: [PATCH 5/8] fuse: don't use ->d_time |
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On Wed, Jun 22, 2016 at 04:35:07PM +0200, Miklos Szeredi wrote: > Store in memory pointed to by ->d_fsdata. Use ->d_allocate() to allocate > the storage. > > We could cast ->d_fsdata directly on 64bit archs, but I don't think this is > worth the extra complexity.
Now, _that_ is interesting:
> +static void fuse_dentry_release(struct dentry *dentry) > +{ > + kfree(dentry->d_fsdata); > +}
What happens to fuse_dentry_revalidate() called on dentry in process of getting dropped? Unlike freeing struct dentry itself, ->d_release() is not RCU-delayed. So you are risking dereference of ->d_fsdata after kfree(); at the very least, it needs RCU-delayed freeing...
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