From: Adrian Hunter <adrian.hunter@intel.com> stable inclusion from stable-v5.10.137 commit b002a71d45bd323101a49f0cade978f1f65849c0 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> --- 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 183a81d5b2f9..2db91121bdaf 100644 --- a/tools/perf/util/dsos.c +++ b/tools/perf/util/dsos.c @@ -20,8 +20,19 @@ 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; } -- 2.20.1