Re: [PATCH] Fix SUNRPC wakeup/execute race condition

[Christophe Saout <christophe@saout.de>]

Am Sonntag, den 05.11.2006, 01:50 -0500 schrieb Trond Myklebust:

> > --- linux-2.6.18/net/sunrpc/sched.c	2006-09-20 05:42:06.000000000 +0200
> > +++ linux/net/sunrpc/sched.c	2006-11-04 20:38:56.000000000 +0100
> > @@ -302,12 +302,9 @@ EXPORT_SYMBOL(__rpc_wait_for_completion_
> >   */
> >  static void rpc_make_runnable(struct rpc_task *task)
> >  {
> > -	int do_ret;
> > -
> >  	BUG_ON(task->tk_timeout_fn);
> > -	do_ret = rpc_test_and_set_running(task);
> >  	rpc_clear_queued(task);
> > -	if (do_ret)
> > +	if (rpc_test_and_set_running(task))
> >  		return;
> >  	if (RPC_IS_ASYNC(task)) {
> >  		int status;
> 
> This fix looks wrong to me. If we've made it to 'rpc_make_runnable',
> then the rpc_task will have already been removed from the
> rpc_wait_queue.

I just flipped the two lines, changed nothing else. Why exactly do you
think that's wrong, I don't see anything particular that could be broken
by chaning the ordering. Anyway, the fsstress has been running for 18
hours straight now without showing any signs of problems.