* [PATCH net] ipv6: Fix mem leak in rt6i_pcpu
@ 2016-07-05 19:10 Martin KaFai Lau
2016-07-05 21:09 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Martin KaFai Lau @ 2016-07-05 19:10 UTC (permalink / raw)
To: netdev; +Cc: kernel-team, Hannes Frederic Sowa, Petr Novopashenniy
It was first reported and reproduced by Petr (thanks!) in
https://bugzilla.kernel.org/show_bug.cgi?id=119581
free_percpu(rt->rt6i_pcpu) used to always happen in ip6_dst_destroy().
However, after fixing a deadlock bug in
commit 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt"),
free_percpu() is not called before setting non_pcpu_rt->rt6i_pcpu to NULL.
It is worth to note that rt6i_pcpu is protected by table->tb6_lock.
kmemleak somehow did not report it. We nailed it down by
observing the pcpu entries in /proc/vmallocinfo (first suggested
by Hannes, thanks!).
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Fixes: 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt")
Reported-by: Petr Novopashenniy <pety@rusnet.ru>
Tested-by: Petr Novopashenniy <pety@rusnet.ru>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Petr Novopashenniy <pety@rusnet.ru>
---
net/ipv6/ip6_fib.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 1bcef23..771be1f 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -177,6 +177,7 @@ static void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
}
}
+ free_percpu(non_pcpu_rt->rt6i_pcpu);
non_pcpu_rt->rt6i_pcpu = NULL;
}
--
2.5.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] ipv6: Fix mem leak in rt6i_pcpu
2016-07-05 19:10 [PATCH net] ipv6: Fix mem leak in rt6i_pcpu Martin KaFai Lau
@ 2016-07-05 21:09 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2016-07-05 21:09 UTC (permalink / raw)
To: kafai; +Cc: netdev, kernel-team, hannes, pety
From: Martin KaFai Lau <kafai@fb.com>
Date: Tue, 5 Jul 2016 12:10:23 -0700
> It was first reported and reproduced by Petr (thanks!) in
> https://bugzilla.kernel.org/show_bug.cgi?id=119581
>
> free_percpu(rt->rt6i_pcpu) used to always happen in ip6_dst_destroy().
>
> However, after fixing a deadlock bug in
> commit 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt"),
> free_percpu() is not called before setting non_pcpu_rt->rt6i_pcpu to NULL.
>
> It is worth to note that rt6i_pcpu is protected by table->tb6_lock.
>
> kmemleak somehow did not report it. We nailed it down by
> observing the pcpu entries in /proc/vmallocinfo (first suggested
> by Hannes, thanks!).
>
> Signed-off-by: Martin KaFai Lau <kafai@fb.com>
> Fixes: 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt")
> Reported-by: Petr Novopashenniy <pety@rusnet.ru>
> Tested-by: Petr Novopashenniy <pety@rusnet.ru>
> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
> Cc: Petr Novopashenniy <pety@rusnet.ru>
Applied and queued up for -stable.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2016-07-05 19:10 [PATCH net] ipv6: Fix mem leak in rt6i_pcpu Martin KaFai Lau
2016-07-05 21:09 ` David Miller
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