perf report: More robust error handling

[deliverable/linux.git] / Documentation / perf_counter / builtin-report.c

diff --git a/Documentation/perf_counter/builtin-report.c b/Documentation/perf_counter/builtin-report.c
index 2d4e4cc655a3867454b687d49c2edb7ba16111e8..a58be7fee4256f753d8a022c2fae92fde74ef57d 100644 (file)
--- a/Documentation/perf_counter/builtin-report.c
+++ b/Documentation/perf_counter/builtin-report.c
@@ -645,6 +645,7 @@ static int __cmd_report(void)
        char *buf;
        event_t *event;
        int ret, rc = EXIT_FAILURE;
+       uint32_t size;
        unsigned long total = 0, total_mmap = 0, total_comm = 0, total_unknown = 0;
 
        input = open(input_name, O_RDONLY);
@@ -680,6 +681,10 @@ remap:
 more:
        event = (event_t *)(buf + head);
 
+       size = event->header.size;
+       if (!size)
+               size = 8;
+
        if (head + event->header.size >= page_size * mmap_window) {
                unsigned long shift = page_size * (head / page_size);
                int ret;
@@ -692,12 +697,9 @@ more:
                goto remap;
        }
 
-
-       if (!event->header.size) {
-               fprintf(stderr, "zero-sized event at file offset %ld\n", offset + head);
-               fprintf(stderr, "skipping %ld bytes of events.\n", stat.st_size - offset - head);
-               goto done;
-       }
+       size = event->header.size;
+       if (!size)
+               goto broken_event;
 
        if (event->header.misc & PERF_EVENT_MISC_OVERFLOW) {
                char level;
@@ -787,15 +789,26 @@ more:
                break;
        }
        default: {
+broken_event:
                fprintf(stderr, "%p [%p]: skipping unknown header type: %d\n",
                        (void *)(offset + head),
                        (void *)(long)(event->header.size),
                        event->header.type);
                total_unknown++;
+
+               /*
+                * assume we lost track of the stream, check alignment, and
+                * increment a single u64 in the hope to catch on again 'soon'.
+                */
+
+               if (unlikely(head & 7))
+                       head &= ~7ULL;
+
+               size = 8;
        }
        }
 
-       head += event->header.size;
+       head += size;
 
        if (offset + head < stat.st_size)
                goto more;