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| author | Alexei Starovoitov <ast@kernel.org> | 2025-02-07 15:45:44 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-02-07 15:45:51 -0800 |
| commit | 310794c219e7b6bd4b21254ac3b871ee989cbece (patch) | |
| tree | d72736640b9d442a717f48ea8413652579e8eb3f /kernel | |
| parent | 517e8a7835e8cfb398a0aeb0133de50e31cae32b (diff) | |
| parent | 7968c6581507052c1c6484ee6c5cbe07381e2dbc (diff) | |
| download | linux-310794c219e7b6bd4b21254ac3b871ee989cbece.tar.gz linux-310794c219e7b6bd4b21254ac3b871ee989cbece.zip | |
Merge branch 'bpf-some-fixes-for-nullness-elision'
Daniel Xu says:
====================
Tow fixes for nullness elision.
Changes from v1:
* Reword commit message in patch 1
* Add tags
====================
Link: https://patch.msgid.link/cover.1738689872.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9971c03adfd5..98354d781678 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9149,10 +9149,11 @@ static int check_reg_const_str(struct bpf_verifier_env *env, return 0; } -/* Returns constant key value if possible, else negative error */ -static s64 get_constant_map_key(struct bpf_verifier_env *env, +/* Returns constant key value in `value` if possible, else negative error */ +static int get_constant_map_key(struct bpf_verifier_env *env, struct bpf_reg_state *key, - u32 key_size) + u32 key_size, + s64 *value) { struct bpf_func_state *state = func(env, key); struct bpf_reg_state *reg; @@ -9179,8 +9180,10 @@ static s64 get_constant_map_key(struct bpf_verifier_env *env, /* First handle precisely tracked STACK_ZERO */ for (i = off; i >= 0 && stype[i] == STACK_ZERO; i--) zero_size++; - if (zero_size >= key_size) + if (zero_size >= key_size) { + *value = 0; return 0; + } /* Check that stack contains a scalar spill of expected size */ if (!is_spilled_scalar_reg(&state->stack[spi])) @@ -9203,9 +9206,12 @@ static s64 get_constant_map_key(struct bpf_verifier_env *env, if (err < 0) return err; - return reg->var_off.value; + *value = reg->var_off.value; + return 0; } +static bool can_elide_value_nullness(enum bpf_map_type type); + static int check_func_arg(struct bpf_verifier_env *env, u32 arg, struct bpf_call_arg_meta *meta, const struct bpf_func_proto *fn, @@ -9354,9 +9360,16 @@ skip_type_check: err = check_helper_mem_access(env, regno, key_size, BPF_READ, false, NULL); if (err) return err; - meta->const_map_key = get_constant_map_key(env, reg, key_size); - if (meta->const_map_key < 0 && meta->const_map_key != -EOPNOTSUPP) - return meta->const_map_key; + if (can_elide_value_nullness(meta->map_ptr->map_type)) { + err = get_constant_map_key(env, reg, key_size, &meta->const_map_key); + if (err < 0) { + meta->const_map_key = -1; + if (err == -EOPNOTSUPP) + err = 0; + else + return err; + } + } break; case ARG_PTR_TO_MAP_VALUE: if (type_may_be_null(arg_type) && register_is_null(reg)) |