From: Alexei Starovoitov <ast@xxxxxxxxxx>
Add light skeleton test for kfunc detection and denylist it for s390.
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
---
tools/testing/selftests/bpf/DENYLIST.s390x | 1 +
.../testing/selftests/bpf/progs/test_ksyms_weak.c | 15 +++++++++++++++
2 files changed, 16 insertions(+)
diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
index 34cb8b2de8ca..c7463f3ec3c0 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -11,6 +11,7 @@ get_stack_raw_tp # user_stack corrupted user stack
iters/testmod_seq* # s390x doesn't support kfuncs in modules yet
kprobe_multi_bench_attach # bpf_program__attach_kprobe_multi_opts unexpected error: -95
kprobe_multi_test # relies on fentry
+ksyms_btf/weak_ksyms* # test_ksyms_weak__open_and_load unexpected error: -22 (kfunc)
ksyms_module # test_ksyms_module__open_and_load unexpected error: -9 (?)
ksyms_module_libbpf # JIT does not support calling kernel function (kfunc)
ksyms_module_lskel # test_ksyms_module_lskel__open_and_load unexpected error: -9 (?)
diff --git a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
index 7003eef0c192..d00268c91e19 100644
--- a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
+++ b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
@@ -20,6 +20,8 @@ __u64 out__non_existent_typed = -1;
/* test existing weak symbols can be resolved. */
extern const struct rq runqueues __ksym __weak; /* typed */
extern const void bpf_prog_active __ksym __weak; /* typeless */
+struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym __weak;
+void bpf_testmod_test_mod_kfunc(int i) __ksym __weak;
/* non-existent weak symbols. */
@@ -29,6 +31,7 @@ extern const void bpf_link_fops1 __ksym __weak;
/* typed symbols, default to zero. */
extern const int bpf_link_fops2 __ksym __weak;
+void invalid_kfunc(void) __ksym __weak;
SEC("raw_tp/sys_enter")
int pass_handler(const void *ctx)
@@ -50,6 +53,18 @@ int pass_handler(const void *ctx)
if (&bpf_link_fops2) /* can't happen */
out__non_existent_typed = (__u64)bpf_per_cpu_ptr(&bpf_link_fops2, 0);
+ if (!bpf_ksym_exists(bpf_task_acquire))
+ /* dead code won't be seen by the verifier */
+ bpf_task_acquire(0);
+
+ if (!bpf_ksym_exists(bpf_testmod_test_mod_kfunc))
+ /* dead code won't be seen by the verifier */
+ bpf_testmod_test_mod_kfunc(0);
+
+ if (bpf_ksym_exists(invalid_kfunc))
+ /* dead code won't be seen by the verifier */
+ invalid_kfunc();
+
return 0;
}
--
2.34.1
