1 files changed, 2 insertions, 0 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 0582f67fbefc..1c173ccb0ef2 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -607,6 +607,8 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist,
         evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, prot,
                                       MAP_SHARED, fd, 0);
         if (evlist->mmap[idx].base == MAP_FAILED) {
+                pr_debug2("failed to mmap perf event ring buffer, error %d\n",
+                          errno);
                 evlist->mmap[idx].base = NULL;
                 return -1;
         }