Re: [PATCH net-next 2/4] bpf/verifier: remove varlen_map_value_access flag
From: Alexei Starovoitov via iovisor-dev <hidden>
Date: 2017-08-22 15:17:27
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 <redacted>