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bpf/verifier: remove varlen_map_value_access flag

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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: f1174f77b5 ("bpf/verifier: rework value tracking")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Edward Cree
2017-08-23 15:10:50 +01:00
committed by David S. Miller
parent df20cb7ec1
commit 1b688a19a9
2 changed files with 12 additions and 30 deletions
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include/linux/bpf_verifier.h
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@ -125,7 +125,6 @@ struct bpf_verifier_env {
u32 id_gen; /* used to generate unique reg IDs */
bool allow_ptr_leaks;
bool seen_direct_write;
bool varlen_map_value_access;
struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
};