On Wed, Apr 24, 2024 at 01:44:50PM +0200, Jiri Olsa wrote:
SNIP
> > see below, even if array of ksym ptrs idea doesn't work out, at least
> > results can be an array (which is cleaner to work with both on BPF and
> > user space sides)
>
> I recall in past we used to do that and we switched to specific values
> to be more explicit I guess.. but it might make sense in here, will try it
>
> SNIP
>
> > > +static int session_check(void *ctx, bool is_return)
> > > +{
> > > + if (bpf_get_current_pid_tgid() >> 32 != pid)
> > > + return 1;
> > > +
> > > + __u64 addr = bpf_get_func_ip(ctx);
> > > +
> > > +#define SET(__var, __addr) ({ \
> > > + if ((const void *) addr == __addr) \
> > > + __var = 1; \
> > > +})
> > > +
> > > + if (is_return) {
> > > + SET(kretprobe_test1_result, &bpf_fentry_test1);
> > > + SET(kretprobe_test2_result, &bpf_fentry_test2);
> > > + SET(kretprobe_test3_result, &bpf_fentry_test3);
> > > + SET(kretprobe_test4_result, &bpf_fentry_test4);
> > > + SET(kretprobe_test5_result, &bpf_fentry_test5);
> > > + SET(kretprobe_test6_result, &bpf_fentry_test6);
> > > + SET(kretprobe_test7_result, &bpf_fentry_test7);
> > > + SET(kretprobe_test8_result, &bpf_fentry_test8);
> > > + } else {
> > > + SET(kprobe_test1_result, &bpf_fentry_test1);
> > > + SET(kprobe_test2_result, &bpf_fentry_test2);
> > > + SET(kprobe_test3_result, &bpf_fentry_test3);
> > > + SET(kprobe_test4_result, &bpf_fentry_test4);
> > > + SET(kprobe_test5_result, &bpf_fentry_test5);
> > > + SET(kprobe_test6_result, &bpf_fentry_test6);
> > > + SET(kprobe_test7_result, &bpf_fentry_test7);
> > > + SET(kprobe_test8_result, &bpf_fentry_test8);
> > > + }
> > > +
> > > +#undef SET
> >
> > curious, have you tried implementing this through a proper for loop? I
> > wonder if something like
> >
> > void *kfuncs[] = { &bpf_fentry_test1, ..., &bpf_fentry_test8 };
> >
> > and then generic loop over this array would work. Can you please try?
>
> yep, will try, let's see if it gets nicer
ok it looks better, I'll send new version
thanks,
jirka
---
diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h
index 14ebe7d9e1a3..180030b5d828 100644
--- a/tools/testing/selftests/bpf/bpf_kfuncs.h
+++ b/tools/testing/selftests/bpf/bpf_kfuncs.h
@@ -75,4 +75,6 @@ extern void bpf_key_put(struct bpf_key *key) __ksym;
extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
struct bpf_dynptr *sig_ptr,
struct bpf_key *trusted_keyring) __ksym;
+
+extern bool bpf_session_is_return(void) __ksym;
#endif
diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
index 51628455b6f5..f6eac16a9339 100644
--- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -4,6 +4,7 @@
#include "trace_helpers.h"
#include "kprobe_multi_empty.skel.h"
#include "kprobe_multi_override.skel.h"
+#include "kprobe_multi_session.skel.h"
#include "bpf/libbpf_internal.h"
#include "bpf/hashmap.h"
@@ -326,6 +327,46 @@ static void test_attach_api_fails(void)
kprobe_multi__destroy(skel);
}
+static void test_session_skel_api(void)
+{
+ struct kprobe_multi_session *skel = NULL;
+ LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+ struct bpf_link *link = NULL;
+ int err, prog_fd;
+
+ skel = kprobe_multi_session__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "kprobe_multi_session__open_and_load"))
+ return;
+
+ skel->bss->pid = getpid();
+
+ err = kprobe_multi_session__attach(skel);
+ if (!ASSERT_OK(err, " kprobe_multi_session__attach"))
+ goto cleanup;
+
+ prog_fd = bpf_program__fd(skel->progs.trigger);
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ ASSERT_OK(err, "test_run");
+ ASSERT_EQ(topts.retval, 0, "test_run");
+
+ /* bpf_fentry_test1-4 trigger return probe, result is 2 */
+ ASSERT_EQ(skel->bss->kprobe_session_result[0], 2, "kprobe_session_result[0]");
+ ASSERT_EQ(skel->bss->kprobe_session_result[1], 2, "kprobe_session_result[1]");
+ ASSERT_EQ(skel->bss->kprobe_session_result[2], 2, "kprobe_session_result[2]");
+ ASSERT_EQ(skel->bss->kprobe_session_result[3], 2, "kprobe_session_result[3]");
+
+ /* bpf_fentry_test5-8 trigger only entry probe, result is 1 */
+ ASSERT_EQ(skel->bss->kprobe_session_result[4], 1, "kprobe_session_result[4]");
+ ASSERT_EQ(skel->bss->kprobe_session_result[5], 1, "kprobe_session_result[5]");
+ ASSERT_EQ(skel->bss->kprobe_session_result[6], 1, "kprobe_session_result[6]");
+ ASSERT_EQ(skel->bss->kprobe_session_result[7], 1, "kprobe_session_result[7]");
+
+cleanup:
+ bpf_link__destroy(link);
+ kprobe_multi_session__destroy(skel);
+}
+
static size_t symbol_hash(long key, void *ctx __maybe_unused)
{
return str_hash((const char *) key);
@@ -690,4 +731,6 @@ void test_kprobe_multi_test(void)
test_attach_api_fails();
if (test__start_subtest("attach_override"))
test_attach_override();
+ if (test__start_subtest("session"))
+ test_session_skel_api();
}
diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi_session.c b/tools/testing/selftests/bpf/progs/kprobe_multi_session.c
new file mode 100644
index 000000000000..3f4137100482
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi_session.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <stdbool.h>
+#include "bpf_kfuncs.h"
+
+char _license[] SEC("license") = "GPL";
+
+extern const void bpf_fentry_test1 __ksym;
+extern const void bpf_fentry_test2 __ksym;
+extern const void bpf_fentry_test3 __ksym;
+extern const void bpf_fentry_test4 __ksym;
+extern const void bpf_fentry_test5 __ksym;
+extern const void bpf_fentry_test6 __ksym;
+extern const void bpf_fentry_test7 __ksym;
+extern const void bpf_fentry_test8 __ksym;
+
+int pid = 0;
+
+__u64 kprobe_session_result[8];
+
+static const void *kfuncs[8] = {
+ &bpf_fentry_test1,
+ &bpf_fentry_test2,
+ &bpf_fentry_test3,
+ &bpf_fentry_test4,
+ &bpf_fentry_test5,
+ &bpf_fentry_test6,
+ &bpf_fentry_test7,
+ &bpf_fentry_test8,
+};
+
+static int session_check(void *ctx, bool is_return)
+{
+ unsigned int i;
+ __u64 addr;
+
+ if (bpf_get_current_pid_tgid() >> 32 != pid)
+ return 1;
+
+ addr = bpf_get_func_ip(ctx);
+
+ for (i = 0; i < 8; i++) {
+ if (kfuncs[i] == (void *) addr) {
+ kprobe_session_result[i]++;
+ break;
+ }
+ }
+
+ /*
+ * Force probes for function bpf_fentry_test[5-8] not to
+ * install and execute the return probe
+ */
+ if (((const void *) addr == &bpf_fentry_test5) ||
+ ((const void *) addr == &bpf_fentry_test6) ||
+ ((const void *) addr == &bpf_fentry_test7) ||
+ ((const void *) addr == &bpf_fentry_test8))
+ return 1;
+
+ return 0;
+}
+
+/*
+ * No tests in here, just to trigger 'bpf_fentry_test*'
+ * through tracing test_run
+ */
+SEC("fentry/bpf_modify_return_test")
+int BPF_PROG(trigger)
+{
+ return 0;
+}
+
+SEC("kprobe.session/bpf_fentry_test*")
+int test_kprobe(struct pt_regs *ctx)
+{
+ return session_check(ctx, bpf_session_is_return());
+}
