From f3982385bc507991f1ed732c3c7907bff703f4d4 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Thu, 24 Jul 2025 09:32:41 -0700 Subject: [PATCH] perf build-id: Reduce size of "size" variable Later clean up of the dso_id to include a build_id will suffer from alignment and size issues. The size can only hold up to a value of BUILD_ID_SIZE (20) and the mmap2 event uses a byte for the value. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250724163302.596743-2-irogers@google.com Signed-off-by: Namhyung Kim --- tools/perf/util/build-id.h | 2 +- tools/perf/util/synthetic-events.c | 8 ++++++-- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h index a212497bfdb0..e3e0a446ff0c 100644 --- a/tools/perf/util/build-id.h +++ b/tools/perf/util/build-id.h @@ -13,7 +13,7 @@ struct build_id { u8 data[BUILD_ID_SIZE]; - size_t size; + u8 size; }; struct dso; diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index 7c00b09e3a93..d3c454174602 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -2248,7 +2248,9 @@ int perf_event__synthesize_build_id(const struct perf_tool *tool, memset(&ev, 0, len); - ev.build_id.size = min(bid->size, sizeof(ev.build_id.build_id)); + ev.build_id.size = bid->size; + if (ev.build_id.size > sizeof(ev.build_id.build_id)) + ev.build_id.size = sizeof(ev.build_id.build_id); memcpy(ev.build_id.build_id, bid->data, ev.build_id.size); ev.build_id.header.type = PERF_RECORD_HEADER_BUILD_ID; ev.build_id.header.misc = misc | PERF_RECORD_MISC_BUILD_ID_SIZE; @@ -2308,7 +2310,9 @@ int perf_event__synthesize_mmap2_build_id(const struct perf_tool *tool, ev.mmap2.len = len; ev.mmap2.pgoff = pgoff; - ev.mmap2.build_id_size = min(bid->size, sizeof(ev.mmap2.build_id)); + ev.mmap2.build_id_size = bid->size; + if (ev.mmap2.build_id_size > sizeof(ev.mmap2.build_id)) + ev.build_id.size = sizeof(ev.mmap2.build_id); memcpy(ev.mmap2.build_id, bid->data, ev.mmap2.build_id_size); ev.mmap2.prot = prot; -- 2.25.1