This is a note to let you know that I've just added the patch titled perf tools: Fix dso_id inode generation comparison to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: perf-tools-fix-dso_id-inode-generation-comparison.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ba0aa2e06d39c3f3767c442051a20824f645b517 Author: Adrian Hunter <adrian.hunter@xxxxxxxxx> Date: Mon Jul 11 12:31:44 2022 +0300 perf tools: Fix dso_id inode generation comparison [ 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@xxxxxxxxx> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> Cc: Ian Rogers <irogers@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: kvm@xxxxxxxxxxxxxxx Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220711093218.10967-2-adrian.hunter@xxxxxxxxx [ Added clarification to the comment from Ian + more detailed explanation from Adrian ] Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> 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; }