selftests/bpf: Add load_kallsyms_refresh function

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>
Link: https://lore.kernel.org/r/20221025134148.3300700-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 9c4be2c..09a16a7 100644 (file)
--- 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 238a9c9..53efde0 100644 (file)
--- 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);