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From: Ian Rogers <irogers@google.com>
To: "Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
	"Jiri Olsa" <jolsa@kernel.org>, "Ian Rogers" <irogers@google.com>,
	"Adrian Hunter" <adrian.hunter@intel.com>,
	"Kan Liang" <kan.liang@linux.intel.com>,
	"Athira Rajeev" <atrajeev@linux.ibm.com>,
	"Kajol Jain" <kjain@linux.ibm.com>,
	"Li Huafei" <lihuafei1@huawei.com>,
	"Steinar H. Gunderson" <sesse@google.com>,
	"James Clark" <james.clark@linaro.org>,
	"Stephen Brennan" <stephen.s.brennan@oracle.com>,
	"Andi Kleen" <ak@linux.intel.com>,
	"Dmitry Vyukov" <dvyukov@google.com>,
	"Zhongqiu Han" <quic_zhonhan@quicinc.com>,
	"Yicong Yang" <yangyicong@hisilicon.com>,
	"Krzysztof Łopatowski" <krzysztof.m.lopatowski@gmail.com>,
	"Dr. David Alan Gilbert" <linux@treblig.org>,
	"Zixian Cai" <fzczx123@gmail.com>,
	"Steve Clevenger" <scclevenger@os.amperecomputing.com>,
	"Thomas Falcon" <thomas.falcon@intel.com>,
	"Martin Liska" <martin.liska@hey.com>,
	"Martin Liška" <m.liska@foxlink.cz>, "Song Liu" <song@kernel.org>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/8] perf build-id: Reduce size of "size" variable
Date: Thu, 24 Apr 2025 12:58:26 -0700	[thread overview]
Message-ID: <20250424195831.1767457-4-irogers@google.com> (raw)
In-Reply-To: <20250424195831.1767457-1-irogers@google.com>

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 <irogers@google.com>
---
 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 2fc4d0537840..68bb7c5fe1b1 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;
-- 
2.49.0.850.g28803427d3-goog


  parent reply	other threads:[~2025-04-24 19:58 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-24 19:58 [PATCH v2 0/8] perf: Default use of build IDs and improvements Ian Rogers
2025-04-24 19:58 ` [PATCH v2 1/8] perf callchain: Always populate the addr_location map when adding IP Ian Rogers
2025-04-24 19:58 ` [PATCH v2 2/8] perf jitdump: Directly mark the jitdump DSO Ian Rogers
2025-04-25 15:12   ` Arnaldo Carvalho de Melo
2025-04-25 16:01     ` Ian Rogers
2025-04-24 19:58 ` Ian Rogers [this message]
2025-04-24 19:58 ` [PATCH v2 4/8] perf build-id: Truncate to avoid overflowing the build_id data Ian Rogers
2025-04-24 19:58 ` [PATCH v2 5/8] perf build-id: Change sprintf functions to snprintf Ian Rogers
2025-04-25 15:09   ` Arnaldo Carvalho de Melo
2025-04-24 19:58 ` [PATCH v2 6/8] perf build-id: Mark DSO in sample callchains Ian Rogers
2025-04-24 19:58 ` [PATCH v2 7/8] perf dso: Move build_id to dso_id Ian Rogers
2025-04-25 17:15   ` Namhyung Kim
2025-04-25 18:46     ` Ian Rogers
2025-04-28 20:04       ` Namhyung Kim
2025-04-28 20:22         ` Ian Rogers
2025-04-24 19:58 ` [PATCH v2 8/8] perf record: Make --buildid-mmap the default Ian Rogers

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