Re: [PATCH] net dst: fix percpu_counter list corruption and poisonoverwritten

From: Xiaotian Feng
Date: Wed Nov 03 2010 - 01:26:04 EST


On 11/03/2010 01:22 PM, Eric Dumazet wrote:
Le mercredi 03 novembre 2010 Ã 10:11 +0800, Xiaotian Feng a Ãcrit :
There're some percpu_counter list corruption and poison overwritten warnings
in recent kernel, which is resulted by fc66f95c.

commit fc66f95c switches to use percpu_counter, in ip6_route_net_init, kernel
init the percpu_counter for dst entries, but, the percpu_counter is never destroyed
in ip6_route_net_exit. So if the related data is freed by kernel, the freed percpu_counter
is still on the list, then if we insert/remove other percpu_counter, list corruption
resulted. Also, if the insert/remove option modifies the ->prev,->next pointer of
the freed value, the poison overwritten is resulted then.

With the following patch, the percpu_counter list corruption and poison overwritten
warnings disappeared.

Signed-off-by: Xiaotian Feng<dfeng@xxxxxxxxxx>
Cc: "David S. Miller"<davem@xxxxxxxxxxxxx>
Cc: Alexey Kuznetsov<kuznet@xxxxxxxxxxxxx>
Cc: "Pekka Savola (ipv6)"<pekkas@xxxxxxxxxx>
Cc: James Morris<jmorris@xxxxxxxxx>
Cc: Hideaki YOSHIFUJI<yoshfuji@xxxxxxxxxxxxxx>
Cc: Patrick McHardy<kaber@xxxxxxxxx>
---

Good catch, thanks !

Any reason you didnt Cc me (the author of the patch) ?
Sorry, I just used get_maintainer.pl to get the cc list...

Acked-by: Eric Dumazet<eric.dumazet@xxxxxxxxx>





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