Re: [PATCH 3.14 83/88] NFS: Fix /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes

From: Trond Myklebust
Date: Wed Sep 03 2014 - 18:18:25 EST

On Wed, Sep 3, 2014 at 6:05 PM, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> 3.14-stable review patch. If anyone has any objections, please let me know.
> ------------------
> From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> commit 65b38851a17472d31fec9019fc3a55b0802dab88 upstream.
> The usage of pid_ns->child_reaper->nsproxy->net_ns in
> nfs_server_list_open and nfs_client_list_open is not safe.
> /proc for a pid namespace can remain mounted after the all of the
> process in that pid namespace have exited. There are also times
> before the initial process in a pid namespace has started or after the
> initial process in a pid namespace has exited where
> pid_ns->child_reaper can be NULL or stale. Making the idiom
> pid_ns->child_reaper->nsproxy a double whammy of problems.
> Luckily all that needs to happen is to move /proc/fs/nfsfs/servers and
> /proc/fs/nfsfs/volumes under /proc/net to /proc/net/nfsfs/servers and
> /proc/net/nfsfs/volumes and add a symlink from the original location,
> and to use seq_open_net as it has been designed.
> Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> Cc: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

...and ditto. Please hold off applying until the commit is fixed in upstream.

Trond Myklebust

Linux NFS client maintainer, PrimaryData

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