[PATCH 3.16 026/306] perf symbols: Fixup symbol sizes before picking best ones

Ben Hutchings
2017-02-16T00:03:24Z

From: Arnaldo Carvalho de Melo <acme@redhat.com>

commit 432746f8e0b6a82ba832b771afe31abd51af6752 upstream.

When we call symbol__fixup_duplicate() we use algorithms to pick the
"best" symbols for cases where there are various functions/aliases to an
address, and those check zero size symbols, which, before calling
symbol__fixup_end() are _all_ symbols in a just parsed kallsyms file.

So first fixup the end, then fixup the duplicates.

Found while trying to figure out why 'perf test vmlinux' failed, see the
output of 'perf test -v vmlinux' to see cases where the symbols picked
as best for vmlinux don't match the ones picked for kallsyms.

Cc: Anton Blanchard <anton@samba.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 694bf407b061 ("perf symbols: Add some heuristics for choosing the best duplicate symbol")
Link: http://lkml.kernel.org/n/tip-rxqvdgr0mqjdxee0kf8i2ufn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
tools/perf/util/symbol-elf.c | 2 +-
tools/perf/util/symbol.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -958,8 +958,8 @@ new_symbol:
* For misannotated, zeroed, ASM function sizes.
*/
if (nr > 0) {
- symbols__fixup_duplicate(&dso->symbols[map->type]);
symbols__fixup_end(&dso->symbols[map->type]);
+ symbols__fixup_duplicate(&dso->symbols[map->type]);
if (kmap) {
/*
* We need to fixup this here too because we create new
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1176,8 +1176,8 @@ int dso__load_kallsyms(struct dso *dso,
if (kallsyms__delta(map, filename, &delta))
return -1;

- symbols__fixup_duplicate(&dso->symbols[map->type]);
symbols__fixup_end(&dso->symbols[map->type]);
+ symbols__fixup_duplicate(&dso->symbols[map->type]);

if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
dso->symtab_type = DSO_BINARY_TYPE__GUEST_KALLSYMS;