Re: [PATCH 2.6.24-rc3] Fix /proc/net breakage

From: David Woodhouse
Date: Thu Dec 06 2007 - 23:52:26 EST


On Mon, 2007-11-26 at 15:17 -0700, Eric W. Biederman wrote:
> Well I clearly goofed when I added the initial network namespace support
> for /proc/net. Currently things work but there are odd details visible
> to user space, even when we have a single network namespace.
>
> Since we do not cache proc_dir_entry dentries at the moment we can
> just modify ->lookup to return a different directory inode depending
> on the network namespace of the process looking at /proc/net, replacing
> the current technique of using a magic and fragile follow_link method.
>
> To accomplish that this patch:
> - introduces a shadow_proc method to allow different dentries to
> be returned from proc_lookup.
> - Removes the old /proc/net follow_link magic
> - Fixes a weakness in our not caching of proc generic dentries.
>
> As shadow_proc uses a task struct to decided which dentry to return we
> can go back later and fix the proc generic caching without modifying any code that
> uses the shadow_proc method.
>
> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> ---
> fs/proc/generic.c | 12 ++++++-
> fs/proc/proc_net.c | 86 +++--------------------------------------------
> include/linux/proc_fs.h | 3 ++
> 3 files changed, 19 insertions(+), 82 deletions(-)

(commit 2b1e300a9dfc3196ccddf6f1d74b91b7af55e416)

This seems to have broken the use of /proc/bus/usb as a mountpoint. It
always appears empty now, whatever's supposed to be mounted there.

--
dwmw2

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