On Thu, May 25, 2017 at 1:10 AM, Jiri Olsa <jo...@redhat.com> wrote:
> On Tue, May 23, 2017 at 12:48:53AM -0700, David Carrillo-Cisneros wrote:
>
> SNIP
>
>> +int perf_event__synthesize_features(struct perf_tool *tool,
>> + struct perf_session *session,
>> + struct perf_evlist *evlist,
>> + perf_event__handler_t process)
>> +{
>> + struct perf_header *header = &session->header;
>> + struct feat_fd fdd;
>> + struct feature_event *fe;
>> + size_t sz, sz_hdr;
>> + int feat, ret;
>> +
>> + sz_hdr = sizeof(fe->header);
>> + sz = sizeof(union perf_event);
>> + /* get a nice alignment */
>> + sz = PERF_ALIGN(sz, getpagesize());
>> +
>> + memset(&fdd, 0, sizeof(fdd));
>> +
>> + fdd.buf = malloc(sz);
>> + if (!fdd.buf)
>> + return -ENOMEM;
>> +
>> + fdd.size = sz - sz_hdr;
>> +
>> + for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) {
>> + if (!feat_ops[feat].has_record) {
>> + pr_debug("No record header feature for header :%d\n",
>> feat);
>> + continue;
>> + }
>> +
>> + fdd.offset = sizeof(*fe);
>> +
>> + ret = feat_ops[feat].write(&fdd, evlist);
>> + if (ret || fdd.offset <= (ssize_t)sizeof(*fe)) {
>> + pr_debug("Error writing feature\n");
>> + continue;
>> + }
>> +
>> + /* fdd.buf may have changed due to realloc in do_write() */
>
> right, so how's ensured the data never cross the maximum event size (0xffff) ?
>
> I think do_write should have some check on that
do_write reallocates ff->buff when it's not large enough.
>
> jirka
