Re: [Stable-review] [07/55] SUNRPC: Fix a race between work-queueand rpc_killall_tasks

[Greg KH]

On Sun, Aug 07, 2011 at 06:38:01PM +0100, Ben Hutchings wrote:
> On Fri, 2011-08-05 at 17:01 -0700, Greg KH wrote:
> > 2.6.32-longterm review patch.  If anyone has any objections, please let us know.
> > 
> > ------------------
> > 
> > From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> > 
> > commit b55c59892e1f3b6c7d4b9ccffb4263e1486fb990 upstream.
> > 
> > Since rpc_killall_tasks may modify the rpc_task's tk_action field
> > without any locking, we need to be careful when dereferencing it.
> [...]
> 
> This isn't nearly careful enough to avoid races.  You must at least use
> the ACCESS_ONCE macro, otherwise the compiler can just optimise away the
> local variable this introduces.

Well, that's an upstream issue as well, right?  Not much I can do here
in the stable updates :)

greg k-h
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