selftests/bpf: Add a test case for kptr_rcu.

Tweak existing map_kptr test to check kptr_rcu.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230303041446.3630-5-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2023-03-02 20:14:44 -08:00 committed by Daniel Borkmann
parent 20c09d92fa
commit 838bd4ac9a

View File

@ -118,6 +118,7 @@ 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))
@ -147,12 +148,23 @@ 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;