From: Adrian Hunter adrian.hunter@intel.com
[ Upstream commit 68566a7cf56bf3148797c218ed45a9de078ef47c ]
Synthesized MMAP events have zero ino_generation, so do not compare them to DSOs with a real ino_generation otherwise we end up with a DSO without a build id.
Fixes: 0e3149f86b99ddab ("perf dso: Move dso_id from 'struct map' to 'struct dso'") Signed-off-by: Adrian Hunter adrian.hunter@intel.com Cc: Andi Kleen ak@linux.intel.com Cc: Ian Rogers irogers@google.com Cc: Jiri Olsa jolsa@kernel.org Cc: kvm@vger.kernel.org Cc: Namhyung Kim namhyung@kernel.org Link: https://lore.kernel.org/r/20220711093218.10967-2-adrian.hunter@intel.com [ Added clarification to the comment from Ian + more detailed explanation from Adrian ] Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/dsos.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c index b97366f77bbf..2bd23e4cf19e 100644 --- a/tools/perf/util/dsos.c +++ b/tools/perf/util/dsos.c @@ -23,8 +23,19 @@ static int __dso_id__cmp(struct dso_id *a, struct dso_id *b) if (a->ino > b->ino) return -1; if (a->ino < b->ino) return 1;
- if (a->ino_generation > b->ino_generation) return -1; - if (a->ino_generation < b->ino_generation) return 1; + /* + * Synthesized MMAP events have zero ino_generation, avoid comparing + * them with MMAP events with actual ino_generation. + * + * I found it harmful because the mismatch resulted in a new + * dso that did not have a build ID whereas the original dso did have a + * build ID. The build ID was essential because the object was not found + * otherwise. - Adrian + */ + if (a->ino_generation && b->ino_generation) { + if (a->ino_generation > b->ino_generation) return -1; + if (a->ino_generation < b->ino_generation) return 1; + }
return 0; }