diff mbox series

[bpf-next,v3,3/3] selftests/bpf: check whether s32 is sufficient for kfunc offset

Message ID 20220130092917.14544-4-hotforest@gmail.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series bpf, arm64: enable kfunc call | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 5 maintainers not CCed: linux-kselftest@vger.kernel.org kpsingh@kernel.org songliubraving@fb.com shuah@kernel.org memxor@gmail.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 84 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next success VM_Test

Commit Message

Hou Tao Jan. 30, 2022, 9:29 a.m. UTC 
From: Hou Tao <houtao1@huawei.com>

In add_kfunc_call(), bpf_kfunc_desc->imm with type s32 is used to
represent the offset of called kfunc from __bpf_call_base, so
add a test to ensure that the offset will not be overflowed.

Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 .../selftests/bpf/prog_tests/ksyms_module.c   | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_module.c b/tools/testing/selftests/bpf/prog_tests/ksyms_module.c
index 997aa90dea64..955a9ede4756 100644
--- a/tools/testing/selftests/bpf/prog_tests/ksyms_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/ksyms_module.c
@@ -3,9 +3,49 @@ 
 
 #include <test_progs.h>
 #include <network_helpers.h>
+#include <trace_helpers.h>
 #include "test_ksyms_module.lskel.h"
 #include "test_ksyms_module.skel.h"
 
+/*
+ * Check whether or not s32 in bpf_kfunc_desc is sufficient
+ * to represent the offset between bpf_testmod_test_mod_kfunc
+ * and __bpf_call_base.
+ */
+static void test_ksyms_module_valid_offset(void)
+{
+	struct test_ksyms_module *skel;
+	unsigned long long kfunc_addr;
+	unsigned long long base_addr;
+	long long actual_offset;
+	int used_offset;
+	int err;
+
+	if (!env.has_testmod) {
+		test__skip();
+		return;
+	}
+
+	/* Ensure kfunc call is supported */
+	skel = test_ksyms_module__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open"))
+		return;
+
+	err = kallsyms_find("bpf_testmod_test_mod_kfunc", &kfunc_addr);
+	if (!ASSERT_OK(err, "find kfunc addr"))
+		goto cleanup;
+
+	err = kallsyms_find("__bpf_call_base", &base_addr);
+	if (!ASSERT_OK(err, "find base addr"))
+		goto cleanup;
+
+	used_offset = kfunc_addr - base_addr;
+	actual_offset = kfunc_addr - base_addr;
+	ASSERT_EQ((long long)used_offset, actual_offset, "kfunc offset overflowed");
+cleanup:
+	test_ksyms_module__destroy(skel);
+}
+
 static void test_ksyms_module_lskel(void)
 {
 	struct test_ksyms_module_lskel *skel;
@@ -55,6 +95,8 @@  static void test_ksyms_module_libbpf(void)
 
 void test_ksyms_module(void)
 {
+	if (test__start_subtest("valid_offset"))
+		test_ksyms_module_valid_offset();
 	if (test__start_subtest("lskel"))
 		test_ksyms_module_lskel();
 	if (test__start_subtest("libbpf"))