Messages in this thread | | | Date | Fri, 18 Jan 2008 17:07:27 -0500 | From | Jeff Layton <> | Subject | Re: [PATCH 4/4] NLM: have nlm_shutdown_hosts kill off all NLM RPC tasks |
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On Fri, 18 Jan 2008 16:43:45 -0500 "J. Bruce Fields" <bfields@fieldses.org> wrote:
> On Mon, Jan 14, 2008 at 09:05:18AM -0500, Jeff Layton wrote: > > If we're shutting down all the nlm_hosts anyway, then it doesn't > > make sense to allow RPC calls to linger. Allowing them to do so can > > mean that the RPC calls can outlive the currently running lockd and > > can lead to a use after free situation. > > I assume that all new rpc calls are created by the lockd thread itself > (which also calls nlm_shutdown_hosts(), which guarantees that there > can't be someone about to make an rpc call using the clnt we're > destroying here? >
I believe that's correct.
> By the way, any idea what the nlm_shutdown_hosts() call in exit_nlm() > is doing? >
Before this patchset, it was possible for more than one lockd to be up at a time, and I suppose there could have been races that would cause both to exit without ever calling nlm_shutdown_hosts.
With this patchset, we may be able to remove that. I suspect that it's probably a noop now. That said, even after spending a fair bit of time in this code, I'm not entirely comfortable with it. I suggest that we take the incremental approach to lockd changes unless someone here is sure :-).
Cheers, -- Jeff Layton <jlayton@redhat.com>
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