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| author | Yonghong Song <yhs@fb.com> | 2018-04-28 22:28:10 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2018-04-29 08:45:53 -0700 |
| commit | afbe1a5b79cd18f0ace9107e6b4cd7aa193e5e52 (patch) | |
| tree | 42800c7f2cf511669b95fc393d398e0c107eb016 /kernel/bpf | |
| parent | 849fa50662fbc8b476d652f8a4e6bdda17b37859 (diff) | |
| download | linux-afbe1a5b79cd18f0ace9107e6b4cd7aa193e5e52.tar.gz | |
bpf: remove never-hit branches in verifier adjust_scalar_min_max_vals
In verifier function adjust_scalar_min_max_vals, when src_known is false and the opcode is BPF_LSH/BPF_RSH, early return will happen in the function. So remove the branch in handling BPF_LSH/BPF_RSH when src_known is false. Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 11 |
1 files changed, 2 insertions, 9 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 988400e283b7..6e3f859b3abf 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2940,10 +2940,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, dst_reg->umin_value <<= umin_val; dst_reg->umax_value <<= umax_val; } - if (src_known) - dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); - else - dst_reg->var_off = tnum_lshift(tnum_unknown, umin_val); + dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); /* We may learn something more from the var_off */ __update_reg_bounds(dst_reg); break; @@ -2971,11 +2968,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, */ dst_reg->smin_value = S64_MIN; dst_reg->smax_value = S64_MAX; - if (src_known) - dst_reg->var_off = tnum_rshift(dst_reg->var_off, - umin_val); - else - dst_reg->var_off = tnum_rshift(tnum_unknown, umin_val); + dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val); dst_reg->umin_value >>= umax_val; dst_reg->umax_value >>= umin_val; /* We may learn something more from the var_off */ |