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Subject[PATCH v2 1/1] perf: Set build-id using build-id header on new mmap records
Date
MMAP records that occur after the build-id header is parsed do not have
their build-id set even if the filename matches an entry from the
header. Set the build-id on these dsos as long as the MMAP record
doesn't have its own build-id set.

This fixes an issue with off target analysis where the local version of
a dso is loaded rather than one from ~/.debug via a build-id.

Reported-by: Denis Nikitin <denik@chromium.org>
Signed-off-by: James Clark <james.clark@arm.com>
---
tools/perf/util/dso.h | 1 +
tools/perf/util/header.c | 1 +
tools/perf/util/map.c | 20 +++++++++++++++++---
3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 011da3924fc1..3a9fd4d389b5 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -167,6 +167,7 @@ struct dso {
enum dso_load_errno load_errno;
u8 adjust_symbols:1;
u8 has_build_id:1;
+ u8 header_build_id:1;
u8 has_srcline:1;
u8 hit:1;
u8 annotate_warned:1;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 6da12e522edc..571d73d4f976 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2200,6 +2200,7 @@ static int __event_process_build_id(struct perf_record_header_build_id *bev,

build_id__init(&bid, bev->data, size);
dso__set_build_id(dso, &bid);
+ dso->header_build_id = 1;

if (dso_space != DSO_SPACE__USER) {
struct kmod_path m = { .name = NULL, };
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 1803d3887afe..e0aa4a254583 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -127,7 +127,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,

if (map != NULL) {
char newfilename[PATH_MAX];
- struct dso *dso;
+ struct dso *dso, *header_bid_dso;
int anon, no_dso, vdso, android;

android = is_android_lib(filename);
@@ -183,9 +183,23 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
}
dso->nsinfo = nsi;

- if (build_id__is_defined(bid))
+ if (build_id__is_defined(bid)) {
dso__set_build_id(dso, bid);
-
+ } else {
+ /*
+ * If the mmap event had no build ID, search for an existing dso from the
+ * build ID header by name. Otherwise only the dso loaded at the time of
+ * reading the header will have the build ID set and all future mmaps will
+ * have it missing.
+ */
+ down_read(&machine->dsos.lock);
+ header_bid_dso = __dsos__find(&machine->dsos, filename, false);
+ up_read(&machine->dsos.lock);
+ if (header_bid_dso && header_bid_dso->header_build_id) {
+ dso__set_build_id(dso, &header_bid_dso->bid);
+ dso->header_build_id = 1;
+ }
+ }
dso__put(dso);
}
return map;
--
2.28.0
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