Re: [PATCH v11 net-next 00/12] eBPF syscall, verifier, testsuite

On 09/10/2014 07:09 AM, Alexei Starovoitov wrote:
...

            struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
                int map_fd;
                void *key;
                union {
                    void *value;
                    void *next_key;
                };
            };

            struct { /* anonymous struct used by BPF_PROG_LOAD command */
                enum bpf_prog_type    prog_type;
                __u32                 insn_cnt;
                const struct bpf_insn *insns;
                const char            *license;
                __u32                 log_level; /* verbosity level of eBPF verifier */
                __u32                 log_size;  /* size of user buffer */
                void                  *log_buf;  /* user supplied buffer */

What is log buffer? Would that mean the verifier will return an error
string if the program will not pass it, or if not, what other data?
I think the man page is missing how to examine the returned verifier
log buffer data.