6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Namhyung Kim <namhyung@xxxxxxxxxx>
[ Upstream commit 23c44f6c83257923b179461694edcf62749bedd5 ]
The build-id events written at the end of the record session are broken
due to unexpected data. The write_buildid() writes the fixed length
event first and then variable length filename.
But a recent change made it write more data in the padding area
accidentally. So readers of the event see zero-filled data for the
next entry and treat it incorrectly. This resulted in wrong kernel
symbols because the kernel DSO loaded a random vmlinux image in the
path as it didn't have a valid build-id.
Fixes: ae39ba16554e ("perf inject: Fix build ID injection")
Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
Link: https://lore.kernel.org/r/Z0aRFFW9xMh3mqKB@xxxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
tools/perf/util/build-id.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 8982f68e7230..e763e8d99a43 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -277,7 +277,7 @@ static int write_buildid(const char *name, size_t name_len, struct build_id *bid
struct perf_record_header_build_id b;
size_t len;
- len = sizeof(b) + name_len + 1;
+ len = name_len + 1;
len = PERF_ALIGN(len, sizeof(u64));
memset(&b, 0, sizeof(b));
@@ -286,7 +286,7 @@ static int write_buildid(const char *name, size_t name_len, struct build_id *bid
misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
b.pid = pid;
b.header.misc = misc;
- b.header.size = len;
+ b.header.size = sizeof(b) + len;
err = do_write(fd, &b, sizeof(b));
if (err < 0)
--
2.39.5
