diff options
Diffstat (limited to 'tools/perf')
| -rw-r--r-- | tools/perf/util/evlist.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 6fb5725821de..85271e54a63b 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -684,6 +684,7 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) struct perf_mmap *md = &evlist->mmap[idx]; u64 head; u64 old = md->prev; + int diff; unsigned char *data = md->base + page_size; union perf_event *event = NULL; @@ -694,6 +695,7 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) return NULL; head = perf_mmap__read_head(md); + diff = head - old; if (evlist->overwrite) { /* * If we're further behind than half the buffer, there's a chance @@ -703,7 +705,6 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) * * In either case, truncate and restart at head. */ - int diff = head - old; if (diff > md->mask / 2 || diff < 0) { fprintf(stderr, "WARNING: failed to keep up with mmap data.\n"); @@ -711,15 +712,21 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) * head points to a known good entry, start there. */ old = head; + diff = 0; } } - if (old != head) { + if (diff >= (int)sizeof(event->header)) { size_t size; event = (union perf_event *)&data[old & md->mask]; size = event->header.size; + if (size < sizeof(event->header) || diff < (int)size) { + event = NULL; + goto broken_event; + } + /* * Event straddles the mmap boundary -- header should always * be inside due to u64 alignment of output. @@ -743,6 +750,7 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx) old += size; } +broken_event: md->prev = old; return event; |