Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [RFC] Suspicious bug in module refcounting | Date | Wed, 11 Feb 2009 00:06:31 +1030 |
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On Tuesday 10 February 2009 21:01:37 Michal Hocko wrote: > On Tue 10-02-09 13:45:07, Rusty Russell wrote: > > On Tuesday 10 February 2009 01:48:31 Michal Hocko wrote: > > > Based on this change, would it make sense to update sys_accept to change > > > __module_get to try_module_get like in the following patch? > > > > I don't think so: > > > > > /* > > > - * We don't need try_module_get here, as the listening socket (sock) > > > - * has the protocol module (sock->ops->owner) held. > > > + * Socket's owner cannot be in unloading path because there > > > + * must be at least one listening reference > > > */ > > > - __module_get(newsock->ops->owner); > > > + if (unlikely(!try_module_get(newsock->ops->owner))) > > > + BUG(); > > > > rmmod --wait can make try_module_get fail even if the reference count isn't > > zero. > > OK, I though that rmmod --wait waits for refcount==0 and then changes > the state.
No, it has to stop all future use, otherwise it's useless under load.
Cheers, Rusty.
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