Function in modules could appear in /proc/kallsyms in random order.
ffffffffa02608a0 t bpf_testmod_loop_test
ffffffffa02600c0 t __traceiter_bpf_testmod_test_writable_bare
ffffffffa0263b60 d __tracepoint_bpf_testmod_test_write_bare
ffffffffa02608c0 T bpf_testmod_test_read
ffffffffa0260d08 t __SCT__tp_func_bpf_testmod_test_writable_bare
ffffffffa0263300 d __SCK__tp_func_bpf_testmod_test_read
ffffffffa0260680 T bpf_testmod_test_write
ffffffffa0260860 t bpf_testmod_test_mod_kfunc
Therefore, we cannot reliably use kallsyms_find_next() to find the end of
a function. Replace it with a simple guess (start + 128). This is good
enough for this test.
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
.../bpf/prog_tests/get_branch_snapshot.c | 7 ++--
tools/testing/selftests/bpf/trace_helpers.c | 36 -------------------
tools/testing/selftests/bpf/trace_helpers.h | 5 ---
3 files changed, 4 insertions(+), 44 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
index d6d70a359aeb5..bc2b6e6d167d4 100644
--- a/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
+++ b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
@@ -91,9 +91,10 @@ void serial_test_get_branch_snapshot(void)
if (!ASSERT_OK(err, "kallsyms_find"))
goto cleanup;
- err = kallsyms_find_next("bpf_testmod_loop_test", &skel->bss->address_high);
- if (!ASSERT_OK(err, "kallsyms_find_next"))
- goto cleanup;
+ /* Just a guess for the end of this function, as module functions
+ * in /proc/kallsyms could come in any order.
+ */
+ skel->bss->address_high = skel->bss->address_low + 128;
err = get_branch_snapshot__attach(skel);
if (!ASSERT_OK(err, "get_branch_snapshot__attach"))
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 5100a169b72b1..7b7f918eda776 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -118,42 +118,6 @@ int kallsyms_find(const char *sym, unsigned long long *addr)
return err;
}
-/* find the address of the next symbol of the same type, this can be used
- * to determine the end of a function.
- */
-int kallsyms_find_next(const char *sym, unsigned long long *addr)
-{
- char type, found_type, name[500];
- unsigned long long value;
- bool found = false;
- int err = 0;
- FILE *f;
-
- f = fopen("/proc/kallsyms", "r");
- if (!f)
- return -EINVAL;
-
- while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) {
- /* Different types of symbols in kernel modules are mixed
- * in /proc/kallsyms. Only return the next matching type.
- * Use tolower() for type so that 'T' matches 't'.
- */
- if (found && found_type == tolower(type)) {
- *addr = value;
- goto out;
- }
- if (strcmp(name, sym) == 0) {
- found = true;
- found_type = tolower(type);
- }
- }
- err = -ENOENT;
-
-out:
- fclose(f);
- return err;
-}
-
void read_trace_pipe(void)
{
int trace_fd;
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index bc8ed86105d94..d907b445524d5 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -16,11 +16,6 @@ long ksym_get_addr(const char *name);
/* open kallsyms and find addresses on the fly, faster than load + search. */
int kallsyms_find(const char *sym, unsigned long long *addr);
-/* find the address of the next symbol, this can be used to determine the
- * end of a function
- */
-int kallsyms_find_next(const char *sym, unsigned long long *addr);
-
void read_trace_pipe(void);
ssize_t get_uprobe_offset(const void *addr, ssize_t base);
--
2.30.2
