[PATCH 2.6]: Fix device leaks in mirred action

[PATCH 2.6]: Fix device leaks in mirred action

[Patrick McHardy]

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When a mirred action is created it takes two references to the
device (dev_get_by_index + dev_hold), but only drops one when
it gets destroyed. It also leaks a reference when a mirred action
is replaced.



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# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2004/11/04 07:28:30+01:00 kaber@coreworks.de 
#   [PKT_SCHED]: Fix device leaks in mirred action
#   
#   Signed-off-by: Patrick McHardy <kaber@trash.net>
# 
# net/sched/mirred.c
#   2004/11/04 07:28:24+01:00 kaber@coreworks.de +2 -1
#   [PKT_SCHED]: Fix device leaks in mirred action
#   
#   Signed-off-by: Patrick McHardy <kaber@trash.net>
# 
diff -Nru a/net/sched/mirred.c b/net/sched/mirred.c
--- a/net/sched/mirred.c	2004-11-04 07:28:59 +01:00
+++ b/net/sched/mirred.c	2004-11-04 07:28:59 +01:00
@@ -138,8 +138,9 @@
 		p->eaction = parm->eaction;
 		if (parm->ifindex) {
 			p->ifindex = parm->ifindex;
+			if (ovr)
+				dev_put(p->dev);
 			p->dev = dev;
-			dev_hold(p->dev); 
 		}
 		spin_unlock(&p->lock);
 	}

Re: [PATCH 2.6]: Fix device leaks in mirred action

[jamal]

On Thu, 2004-11-04 at 01:30, Patrick McHardy wrote:
> When a mirred action is created it takes two references to the
> device (dev_get_by_index + dev_hold), but only drops one when
> it gets destroyed. 

Good catch.
The correct fix is to remove the dev_hold(p->dev) call.

> It also leaks a reference when a mirred action
> is replaced.

How? Is this patch supposed to fix that?

cheers,
jamal

Re: [PATCH 2.6]: Fix device leaks in mirred action

[Patrick McHardy]

jamal wrote:

>>It also leaks a reference when a mirred action
>>is replaced.
>>    
>>
>
>How? Is this patch supposed to fix that?
>  
>
+                       if (ovr)
+                               dev_put(p->dev);
                        p->dev = dev;

By dropping the reference before replacing it.

Regards
Patrick

Re: [PATCH 2.6]: Fix device leaks in mirred action

[jamal]

On Thu, 2004-11-04 at 09:58, Patrick McHardy wrote:
> jamal wrote:
> 
> >>It also leaks a reference when a mirred action
> >>is replaced.
> >
> >How? Is this patch supposed to fix that?
> >  
> >
> +                       if (ovr)
> +                               dev_put(p->dev);
>                         p->dev = dev;
> 
> By dropping the reference before replacing it.
> 

Ok, makes sense. Thanks Patrick.
Dave please apply the patch in its entirety.

cheers,
jamal