tests verify we get 0 return value from bpf_trace_print()
using %pT format specifier with various modifiers/pointer
values.
Signed-off-by: Alan Maguire <[email protected]>
---
.../selftests/bpf/prog_tests/trace_printk_btf.c | 45 +++++++++++++++++++++
.../selftests/bpf/progs/netif_receive_skb.c | 47 ++++++++++++++++++++++
2 files changed, 92 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/trace_printk_btf.c
create mode 100644 tools/testing/selftests/bpf/progs/netif_receive_skb.c
diff --git a/tools/testing/selftests/bpf/prog_tests/trace_printk_btf.c b/tools/testing/selftests/bpf/prog_tests/trace_printk_btf.c
new file mode 100644
index 0000000..791eb97
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/trace_printk_btf.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+
+#include "netif_receive_skb.skel.h"
+
+void test_trace_printk_btf(void)
+{
+ struct netif_receive_skb *skel;
+ struct netif_receive_skb__bss *bss;
+ int err, duration = 0;
+
+ skel = netif_receive_skb__open();
+ if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+ return;
+
+ err = netif_receive_skb__load(skel);
+ if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
+ goto cleanup;
+
+ bss = skel->bss;
+
+ err = netif_receive_skb__attach(skel);
+ if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+ goto cleanup;
+
+ /* generate receive event */
+ system("ping -c 1 127.0.0.1 >/dev/null");
+
+ /*
+ * Make sure netif_receive_skb program was triggered
+ * and it set expected return values from bpf_trace_printk()s
+ * and all tests ran.
+ */
+ if (CHECK(bss->ret <= 0,
+ "bpf_trace_printk: got return value",
+ "ret <= 0 %d test %d\n", bss->ret, bss->num_subtests))
+ goto cleanup;
+
+ CHECK(bss->num_subtests != bss->ran_subtests, "check all subtests ran",
+ "only ran %d of %d tests\n", bss->num_subtests,
+ bss->ran_subtests);
+
+cleanup:
+ netif_receive_skb__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/netif_receive_skb.c b/tools/testing/selftests/bpf/progs/netif_receive_skb.c
new file mode 100644
index 0000000..03ca1d8
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/netif_receive_skb.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Oracle and/or its affiliates. */
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+int ret;
+int num_subtests;
+int ran_subtests;
+
+#define CHECK_PRINTK(_fmt, _p, res) \
+ do { \
+ char fmt[] = _fmt; \
+ ++num_subtests; \
+ if (ret >= 0) { \
+ ++ran_subtests; \
+ ret = bpf_trace_printk(fmt, sizeof(fmt), (_p)); \
+ } \
+ } while (0)
+
+/* TRACE_EVENT(netif_receive_skb,
+ * TP_PROTO(struct sk_buff *skb),
+ */
+SEC("tp_btf/netif_receive_skb")
+int BPF_PROG(trace_netif_receive_skb, struct sk_buff *skb)
+{
+ char skb_type[] = "struct sk_buff";
+ struct btf_ptr nullp = { .ptr = 0, .type = skb_type };
+ struct btf_ptr p = { .ptr = skb, .type = skb_type };
+
+ CHECK_PRINTK("%pT\n", &p, &res);
+ CHECK_PRINTK("%pTc\n", &p, &res);
+ CHECK_PRINTK("%pTN\n", &p, &res);
+ CHECK_PRINTK("%pTx\n", &p, &res);
+ CHECK_PRINTK("%pT0\n", &p, &res);
+ CHECK_PRINTK("%pTcNx0\n", &p, &res);
+ CHECK_PRINTK("%pT\n", &nullp, &res);
+ CHECK_PRINTK("%pTc\n", &nullp, &res);
+ CHECK_PRINTK("%pTN\n", &nullp, &res);
+ CHECK_PRINTK("%pTx\n", &nullp, &res);
+ CHECK_PRINTK("%pT0\n", &nullp, &res);
+ CHECK_PRINTK("%pTcNx0\n", &nullp, &res);
+
+ return 0;
+}
--
1.8.3.1
On Tue, Jun 23, 2020 at 5:12 AM Alan Maguire <[email protected]> wrote:
>
> tests verify we get 0 return value from bpf_trace_print()
> using %pT format specifier with various modifiers/pointer
> values.
>
> Signed-off-by: Alan Maguire <[email protected]>
> ---
Acked-by: Andrii Nakryiko <[email protected]>
> .../selftests/bpf/prog_tests/trace_printk_btf.c | 45 +++++++++++++++++++++
> .../selftests/bpf/progs/netif_receive_skb.c | 47 ++++++++++++++++++++++
> 2 files changed, 92 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/trace_printk_btf.c
> create mode 100644 tools/testing/selftests/bpf/progs/netif_receive_skb.c
>
[...]
> diff --git a/tools/testing/selftests/bpf/progs/netif_receive_skb.c b/tools/testing/selftests/bpf/progs/netif_receive_skb.c
> new file mode 100644
> index 0000000..03ca1d8
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/netif_receive_skb.c
> @@ -0,0 +1,47 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2020, Oracle and/or its affiliates. */
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +
> +char _license[] SEC("license") = "GPL";
> +
> +int ret;
> +int num_subtests;
> +int ran_subtests;
oh, interesting, so Clang doesn't put these into the COM section
anymore? We used to need to explicitly zero-initialize these global
vars because of that.
> +
> +#define CHECK_PRINTK(_fmt, _p, res) \
> + do { \
> + char fmt[] = _fmt; \
pro tip: you can use `static const char fmt[] = _fmt` and it will just work.
> + ++num_subtests; \
> + if (ret >= 0) { \
> + ++ran_subtests; \
> + ret = bpf_trace_printk(fmt, sizeof(fmt), (_p)); \
> + } \
> + } while (0)
> +
> +/* TRACE_EVENT(netif_receive_skb,
> + * TP_PROTO(struct sk_buff *skb),
> + */
> +SEC("tp_btf/netif_receive_skb")
> +int BPF_PROG(trace_netif_receive_skb, struct sk_buff *skb)
> +{
> + char skb_type[] = "struct sk_buff";
same, `static const char` will generate more optimal code (good to
have good examples in selftests for people to follow). But don't
bother re-spinning just for this.
> + struct btf_ptr nullp = { .ptr = 0, .type = skb_type };
> + struct btf_ptr p = { .ptr = skb, .type = skb_type };
> +
> + CHECK_PRINTK("%pT\n", &p, &res);
> + CHECK_PRINTK("%pTc\n", &p, &res);
> + CHECK_PRINTK("%pTN\n", &p, &res);
> + CHECK_PRINTK("%pTx\n", &p, &res);
> + CHECK_PRINTK("%pT0\n", &p, &res);
> + CHECK_PRINTK("%pTcNx0\n", &p, &res);
> + CHECK_PRINTK("%pT\n", &nullp, &res);
> + CHECK_PRINTK("%pTc\n", &nullp, &res);
> + CHECK_PRINTK("%pTN\n", &nullp, &res);
> + CHECK_PRINTK("%pTx\n", &nullp, &res);
> + CHECK_PRINTK("%pT0\n", &nullp, &res);
> + CHECK_PRINTK("%pTcNx0\n", &nullp, &res);
> +
> + return 0;
> +}
> --
> 1.8.3.1
>