Messages in this thread | | | Subject | Re: [PATCH] fix race in mark_mounts_for_expiry() | From | Miklos Szeredi <> | Date | Wed, 18 May 2005 15:21:00 +0200 |
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> And I think you're just adding to the case for removing mnt_namespace > entirely. We'd still keep CLONE_NS, and users currently using > namespaces (in the normal ways) would see no difference. > > mnt_namespace has these visible effects: > > - Prevents some tasks from mounting/umounting in a "foreign" > namespace, even when they are granted access to the directory > tree of the foreign namespace. > > It's not clear if the restriction is a useful security tool. > > - Causes every mount in a mount tree to be detached (independently), > when last task associated with a namespace is destroyed.
I don't understand. The tree _has_ to be detached when no task uses the namespace. That is the main purpose of the namespace structure, to provide an anchor for the mount tree.
> And this invisible effect: > > - More concurrency than a global mount lock would have.
This is the key issue I think. It may even have security implications in the future if we want to allow unprivileged mounts : a user could DoS the system by just doing lots of mounts umounts in a private namespace.
Miklos
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