netdev - Re: [PATCH net-next] net/ipv6: stop leaking percpu memory in fib6 info

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Message-Id: <20181009040335.GC28063@rapoport-lnx>
Date:   Tue, 9 Oct 2018 07:03:36 +0300
From:   Mike Rapoport <rppt@...ux.vnet.ibm.com>
To:     David Ahern <dsahern@...il.com>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        stable@...r.kernel.org
Subject: Re: [PATCH net-next] net/ipv6: stop leaking percpu memory in fib6
 info

On Mon, Oct 08, 2018 at 12:15:54PM -0600, David Ahern wrote:
> On 10/8/18 6:06 AM, Mike Rapoport wrote:
> > The fib6_info_alloc() function allocates percpu memory to hold per CPU
> > pointers to rt6_info, but this memory is never freed. Fix it.
> > 
> > Fixes: a64efe142f5e ("net/ipv6: introduce fib6_info struct and helpers")
> > 
> > Signed-off-by: Mike Rapoport <rppt@...ux.vnet.ibm.com>
> > Cc: stable@...r.kernel.org
> > ---
> >  net/ipv6/ip6_fib.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
> > index cf709eadc932..cc7de7eb8b9c 100644
> > --- a/net/ipv6/ip6_fib.c
> > +++ b/net/ipv6/ip6_fib.c
> > @@ -194,6 +194,8 @@ void fib6_info_destroy_rcu(struct rcu_head *head)
> >  				*ppcpu_rt = NULL;
> >  			}
> >  		}
> > +
> > +		free_percpu(f6i->rt6i_pcpu);
> >  	}
> >  
> >  	lwtstate_put(f6i->fib6_nh.nh_lwtstate);
> > 
> 
> Odd that KMEMLEAK is not detecting this. Thanks for the fix.

There's a comment in kmemleak that says:

	/*
	 * Percpu allocations are only scanned and not reported as leaks
	 * (min_count is set to 0).
	 */

No idea why, though...
 
> Reviewed-by: David Ahern <dsahern@...il.com>
> 

-- 
Sincerely yours,
Mike.