lkml.org 
[lkml]   [2009]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [RFC] Suspicious bug in module refcounting
Date
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.


\
 
 \ /
  Last update: 2009-02-10 14:39    [W:0.212 / U:0.424 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site