bpf: log PTR_TO_MEM memory size in verifier log

Emit valid memory size addressable through PTR_TO_MEM register.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231204233931.49758-2-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

kernel/bpf/log.c

@@ -682,6 +682,10 @@ static void print_reg_state(struct bpf_verifier_env *env,
 		verbose_a("r=");
 		verbose_unum(env, reg->range);
 	}
+	if (base_type(t) == PTR_TO_MEM) {
+		verbose_a("sz=");
+		verbose_unum(env, reg->mem_size);
+	}
 	if (tnum_is_const(reg->var_off)) {
 		/* a pointer register with fixed offset */
 		if (reg->var_off.value) {