Add a file_offset field to struct perf_sample so that event processing callbacks can report the byte offset of the problematic event in perf.data, letting users cross-reference with 'perf report -D' output. Set sample.file_offset in perf_session__deliver_event(), which is the common entry point for both file mode (mmap'd offset) and pipe mode (running byte counter from __perf_session__process_pipe_events). The assignment is placed after evsel__parse_sample(), which zeroes the struct via memset. Preserve file_offset through the deferred callchain delivery path by storing it in struct deferred_event and restoring it after evlist__parse_sample() in both evlist__deliver_deferred_callchain() and session__flush_deferred_samples(). Subsequent patches will use this field in skip/stop warning messages. Reviewed-by: Ian Rogers <irogers@google.com> Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>