diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2023-11-17 19:46:20 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-11-18 11:39:59 -0800 |
| commit | 0c95c9fdb696f35c7864785ba84cb9a50152daff (patch) | |
| tree | 909fcb7acbc43862d80a67c68c62e4b41b09b16d /kernel/bpf/log.c | |
| parent | 67d43dfbb42d6575304daea67733c88fbf536a1c (diff) | |
bpf: emit map name in register state if applicable and available
In complicated real-world applications, whenever debugging some
verification error through verifier log, it often would be very useful
to see map name for PTR_TO_MAP_VALUE register. Usually this needs to be
inferred from key/value sizes and maybe trying to guess C code location,
but it's not always clear.
Given verifier has the name, and it's never too long, let's just emit it
for ptr_to_map_key, ptr_to_map_value, and const_ptr_to_map registers. We
reshuffle the order a bit, so that map name, key size, and value size
appear before offset and immediate values, which seems like a more
logical order.
Current output:
R1_w=map_ptr(map=array_map,ks=4,vs=8,off=0,imm=0)
But we'll get rid of useless off=0 and imm=0 parts in the next patch.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231118034623.3320920-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/log.c')
| -rw-r--r-- | kernel/bpf/log.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index 97a1641e848e..c209ab1ec2b5 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -553,6 +553,17 @@ static void print_scalar_ranges(struct bpf_verifier_env *env, } } +static bool type_is_map_ptr(enum bpf_reg_type t) { + switch (base_type(t)) { + case CONST_PTR_TO_MAP: + case PTR_TO_MAP_KEY: + case PTR_TO_MAP_VALUE: + return true; + default: + return false; + } +} + static void print_reg_state(struct bpf_verifier_env *env, const struct bpf_reg_state *reg) { enum bpf_reg_type t; @@ -584,16 +595,17 @@ static void print_reg_state(struct bpf_verifier_env *env, const struct bpf_reg_s verbose_a("ref_obj_id=%d", reg->ref_obj_id); if (type_is_non_owning_ref(reg->type)) verbose_a("%s", "non_own_ref"); + if (type_is_map_ptr(t)) { + if (reg->map_ptr->name[0]) + verbose_a("map=%s", reg->map_ptr->name); + verbose_a("ks=%d,vs=%d", + reg->map_ptr->key_size, + reg->map_ptr->value_size); + } if (t != SCALAR_VALUE) verbose_a("off=%d", reg->off); if (type_is_pkt_pointer(t)) verbose_a("r=%d", reg->range); - else if (base_type(t) == CONST_PTR_TO_MAP || - base_type(t) == PTR_TO_MAP_KEY || - base_type(t) == PTR_TO_MAP_VALUE) - verbose_a("ks=%d,vs=%d", - reg->map_ptr->key_size, - reg->map_ptr->value_size); if (tnum_is_const(reg->var_off)) { /* Typically an immediate SCALAR_VALUE, but * could be a pointer whose offset is too big |