Re: [PATCH] Relay : fix cpu offline problem

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

Ah, great, I did not see it passing by. Thanks !

Mathieu

* Lai Jiangshan (laijs@cn.fujitsu.com) wrote:
> Hi, Mathieu Desnoyers
> 
> I have fixed this problem in mainline.
> http://lkml.org/lkml/2008/11/14/74
> 
> Lai
> 
> Mathieu Desnoyers wrote:
> > Here is a fix for how relay handles cpu hotplug in the allocation error path. If
> > a cpu goes down while allocating, it may result in a buffer never being freed.
> > 
> > Lai Jiangshan originally identified this problem in the LTTng fork of
> > relay (ltt-relay-alloc). Here is the fix which applies to the original
> > kernel/relay.c.
> > 
> > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> > CC: Lai Jiangshan <laijs@cn.fujitsu.com>
> > CC: Tom Zanussi <zanussi@comcast.net>
> > ---
> >  kernel/relay.c |    7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> > 
> > Index: linux-2.6-lttng/kernel/relay.c
> > ===================================================================
> > --- linux-2.6-lttng.orig/kernel/relay.c	2008-12-09 10:58:45.000000000 -0500
> > +++ linux-2.6-lttng/kernel/relay.c	2008-12-09 11:09:58.000000000 -0500
> > @@ -611,10 +611,9 @@ struct rchan *relay_open(const char *bas
> >  	return chan;
> >  
> >  free_bufs:
> > -	for_each_online_cpu(i) {
> > -		if (!chan->buf[i])
> > -			break;
> > -		relay_close_buf(chan->buf[i]);
> > +	for_each_possible_cpu(i) {
> > +		if (chan->buf[i])
> > +			relay_close_buf(chan->buf[i]);
> >  	}
> >  
> >  	kref_put(&chan->kref, relay_destroy_channel);
> 
> 

-- 
Mathieu Desnoyers
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