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From: Alexei Starovoitov via iovisor-dev <iovisor-dev-9jONkmmOlFHEE9lA1F8Ukti2O/JbrIOy@public.gmane.org>
Subject: Re: [PATCH net-next 2/4] bpf/verifier: remove
 varlen_map_value_access flag
Date: Tue, 22 Aug 2017 08:17:27 -0700
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To: Edward Cree <ecree-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>, <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>, Alexei
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On 8/22/17 6:26 AM, Edward Cree wrote:
> The optimisation it does is broken when the 'new' register value has a
>  variable offset and the 'old' was constant.  I broke it with my pointer
>  types unification (see Fixes tag below), before which the 'new' value
>  would have type PTR_TO_MAP_VALUE_ADJ and would thus not compare equal;
>  other changes in that patch mean that its original behaviour (ignore
>  min/max values) cannot be restored.
> Tests on a sample set of cilium programs show no change in count of
>  processed instructions.
>
> Fixes: f1174f77b50c ("bpf/verifier: rework value tracking")
> Signed-off-by: Edward Cree <ecree-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>

Acked-by: Alexei Starovoitov <ast-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>