[PATCHv3 bpf-next 5/8] selftests/bpf: Add load_kallsyms_refresh function

Jiri Olsa
2022-10-25T13:42:55Z

Adding load_kallsyms_refresh function to re-read symbols from
/proc/kallsyms file.

This will be needed to get proper functions addresses from
bpf_testmod.ko module, which is loaded/unloaded several times
during the tests run, so symbols might be already old when
we need to use them.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/testing/selftests/bpf/trace_helpers.c | 20 +++++++++++++-------
tools/testing/selftests/bpf/trace_helpers.h | 2 ++
2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 9c4be2cdb21a..09a16a77bae4 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -23,7 +23,7 @@ static int ksym_cmp(const void *p1, const void *p2)
return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
}

-int load_kallsyms(void)
+int load_kallsyms_refresh(void)
{
FILE *f;
char func[256], buf[256];
@@ -31,12 +31,7 @@ int load_kallsyms(void)
void *addr;
int i = 0;

- /*
- * This is called/used from multiplace places,
- * load symbols just once.
- */
- if (sym_cnt)
- return 0;
+ sym_cnt = 0;

f = fopen("/proc/kallsyms", "r");
if (!f)
@@ -57,6 +52,17 @@ int load_kallsyms(void)
return 0;
}

+int load_kallsyms(void)
+{
+ /*
+ * This is called/used from multiplace places,
+ * load symbols just once.
+ */
+ if (sym_cnt)
+ return 0;
+ return load_kallsyms_refresh();
+}
+
struct ksym *ksym_search(long key)
{
int start = 0, end = sym_cnt;
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index 238a9c98cde2..53efde0e2998 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -10,6 +10,8 @@ struct ksym {
};

int load_kallsyms(void);
+int load_kallsyms_refresh(void);
+
struct ksym *ksym_search(long key);
long ksym_get_addr(const char *name);

--
2.37.3