[PATCH v3 bpf-next 4/5] selftests/bpf: Add a test case for kptr_rcu.
From: Alexei Starovoitov <hidden>
Date: 2023-02-28 04:02:34
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds
From: Alexei Starovoitov <ast@kernel.org> Tweak existing map_kptr test to check kptr_rcu. Signed-off-by: Alexei Starovoitov <ast@kernel.org> --- tools/testing/selftests/bpf/progs/map_kptr.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/map_kptr.c b/tools/testing/selftests/bpf/progs/map_kptr.c
index 4a7da6cb5800..b041234ec68d 100644
--- a/tools/testing/selftests/bpf/progs/map_kptr.c
+++ b/tools/testing/selftests/bpf/progs/map_kptr.c@@ -61,6 +61,7 @@ extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp extern struct prog_test_ref_kfunc * bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __ksym; extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; +void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) __ksym; #define WRITE_ONCE(x, val) ((*(volatile typeof(x) *) &(x)) = (val))
@@ -90,12 +91,23 @@ static void test_kptr_ref(struct map_value *v) WRITE_ONCE(v->unref_ptr, p); if (!p) return; + /* + * p is rcu_ptr_prog_test_ref_kfunc, + * because bpf prog is non-sleepable and runs in RCU CS. + * p can be passed to kfunc that requires KF_RCU. + */ + bpf_kfunc_call_test_ref(p); if (p->a + p->b > 100) return; /* store NULL */ p = bpf_kptr_xchg(&v->ref_ptr, NULL); if (!p) return; + /* + * p is trusted_ptr_prog_test_ref_kfunc. + * p can be passed to kfunc that requires KF_RCU. + */ + bpf_kfunc_call_test_ref(p); if (p->a + p->b > 100) { bpf_kfunc_call_test_release(p); return;
@@ -288,6 +300,8 @@ int test_map_kptr_ref2(struct __sk_buff *ctx) if (p_st->cnt.refs.counter != 2) return 6; + /* p_st is MEM_RCU, because we're in RCU CS */ + bpf_kfunc_call_test_ref(p_st); return 0; }
--
2.30.2