Re: [PATCH] ipvs: changes related to service usecnt

To: Julian Anastasov <ja@xxxxxx>
Subject: Re: [PATCH] ipvs: changes related to service usecnt
Cc: Patrick McHardy <kaber@xxxxxxxxx>, lvs-devel@xxxxxxxxxxxxxxx, netfilter-devel@xxxxxxxxxxxxxxx
From: Simon Horman <horms@xxxxxxxxxxxx>
Date: Sun, 19 Sep 2010 20:48:00 +0900
On Sat, Sep 18, 2010 at 05:18:46PM +0300, Julian Anastasov wrote:
>       Change the usage of svc usecnt during command execution:
> - we check if svc is registered but we do not need to hold usecnt
> reference while under __ip_vs_mutex, only the packet handling needs
> it during scheduling
> - change __ip_vs_service_get to __ip_vs_service_find and
> __ip_vs_svc_fwm_get to __ip_vs_svc_fwm_find because now caller
> will increase svc->usecnt
> - put common code that calls update_service in __ip_vs_update_dest
> - put common code in ip_vs_unlink_service() and use it to unregister
> the service
> - add comment that svc should not be accessed after ip_vs_del_service 
> anymore
> - all IP_VS_WAIT_WHILE calls are now unified: usecnt > 0
> - Properly log the app ports
>       As result, some problems are fixed:
> - possible use-after-free of svc in ip_vs_genl_set_cmd after
> ip_vs_del_service because our usecnt reference does not guarantee that
> svc is not freed on refcnt==0, eg. when no dests are moved to trash
> - possible usecnt leak in do_ip_vs_set_ctl after ip_vs_del_service
> when the service is not freed now, for example, when some
> destionations are moved into trash and svc->refcnt remains above 0.
> It is harmless because svc is not in hash anymore.
> Signed-off-by: Julian Anastasov <ja@xxxxxx>

Hi Julian,

thats a pretty big patch to review, but it looks good to me.

Acked-by: Simon Horman <horms@xxxxxxxxxxxx>
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