From: Al Viro <viro@ZenIV.linux.org.uk>
To: Miklos Szeredi <mszeredi@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 5/8] fuse: don't use ->d_time
Date: Wed, 22 Jun 2016 17:46:12 +0100 [thread overview]
Message-ID: <20160622164612.GP14480@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1466606110-24297-6-git-send-email-mszeredi@redhat.com>
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...
next prev parent reply other threads:[~2016-06-22 16:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 14:35 [PATCH 0/8] remove d_time from dentry Miklos Szeredi
2016-06-22 14:35 ` [PATCH 1/8] vfs: new d_allocate method Miklos Szeredi
2016-06-22 17:02 ` Al Viro
2016-06-22 20:33 ` Miklos Szeredi
2016-06-22 14:35 ` [PATCH 2/8] ceph: don't use ->d_time Miklos Szeredi
2016-06-23 6:21 ` Yan, Zheng
2016-06-28 8:09 ` Miklos Szeredi
2016-06-28 8:39 ` Yan, Zheng
2016-06-22 14:35 ` [PATCH 3/8] cifs: " Miklos Szeredi
2016-06-22 14:35 ` [PATCH 4/8] vfat: " Miklos Szeredi
2016-06-22 14:35 ` [PATCH 5/8] fuse: " Miklos Szeredi
2016-06-22 16:46 ` Al Viro [this message]
2016-06-22 14:35 ` [PATCH 6/8] nfs: " Miklos Szeredi
2016-06-22 16:48 ` Al Viro
2016-06-22 14:35 ` [PATCH 7/8] ncpfs: " Miklos Szeredi
2016-06-22 16:52 ` Al Viro
2016-06-22 14:35 ` [PATCH 8/8] vfs: remove ->d_time Miklos Szeredi
2016-06-22 21:21 ` [PATCH 0/8] remove d_time from dentry Miklos Szeredi
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