On 7/26/24 8:39 AM, Leon Hwang wrote:
Add a selftest to confirm the issue, which gets -EINVAL when update
attached freplace prog to prog_array map, has been fixed.
cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
327/25 tailcalls/tailcall_freplace:OK
327 tailcalls:OK
Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Leon Hwang <leon.hwang@xxxxxxxxx>
LGTM with some comments below.
Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx>
---
.../selftests/bpf/prog_tests/tailcalls.c | 65 ++++++++++++++++++-
.../selftests/bpf/progs/tailcall_freplace.c | 25 +++++++
.../testing/selftests/bpf/progs/tc_bpf2bpf.c | 21 ++++++
3 files changed, 110 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/progs/tailcall_freplace.c
create mode 100644 tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
index e01fabb8cc415..21c5a37846ade 100644
--- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c
+++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
@@ -5,7 +5,8 @@
#include "tailcall_poke.skel.h"
#include "tailcall_bpf2bpf_hierarchy2.skel.h"
#include "tailcall_bpf2bpf_hierarchy3.skel.h"
-
+#include "tailcall_freplace.skel.h"
+#include "tc_bpf2bpf.skel.h"
/* test_tailcall_1 checks basic functionality by patching multiple locations
* in a single program for a single tail call slot with nop->jmp, jmp->nop
@@ -1495,6 +1496,66 @@ static void test_tailcall_bpf2bpf_hierarchy_3(void)
RUN_TESTS(tailcall_bpf2bpf_hierarchy3);
}
+/* test_tailcall_freplace checks that the attached freplace prog is OK to
+ * update the prog_array map.
+ */
+static void test_tailcall_freplace(void)
+{
+ struct tailcall_freplace *freplace_skel = NULL;
+ struct bpf_link *freplace_link = NULL;
+ struct bpf_program *freplace_prog;
+ struct tc_bpf2bpf *tc_skel = NULL;
+ int prog_fd, map_fd;
+ char buff[128] = {};
+ int err, key;
+
+ LIBBPF_OPTS(bpf_test_run_opts, topts,
+ .data_in = buff,
+ .data_size_in = sizeof(buff),
+ .repeat = 1,
+ );
+
+ freplace_skel = tailcall_freplace__open();
+ if (!ASSERT_OK_PTR(freplace_skel, "tailcall_freplace__open"))
+ return;
+
+ tc_skel = tc_bpf2bpf__open_and_load();
+ if (!ASSERT_OK_PTR(tc_skel, "tc_bpf2bpf__open_and_load"))
+ goto out;
+
+ prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
+ freplace_prog = freplace_skel->progs.entry_freplace;
+ err = bpf_program__set_attach_target(freplace_prog, prog_fd, "subprog");
+ if (!ASSERT_OK(err, "set_attach_target"))
+ goto out;
+
+ err = tailcall_freplace__load(freplace_skel);
+ if (!ASSERT_OK(err, "tailcall_freplace__load"))
+ goto out;
+
+ freplace_link = bpf_program__attach_freplace(freplace_prog, prog_fd,
+ "subprog");
+ if (!ASSERT_OK_PTR(freplace_link, "attach_freplace"))
+ goto out;
+
+ map_fd = bpf_map__fd(freplace_skel->maps.jmp_table);
+ prog_fd = bpf_program__fd(freplace_prog);
+ key = 0;
+ err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
+ if (!ASSERT_OK(err, "update jmp_table"))
+ goto out;
+
+ prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ ASSERT_OK(err, "test_run");
+ ASSERT_EQ(topts.retval, 34, "test_run retval");
+
+out:
+ bpf_link__destroy(freplace_link);
+ tc_bpf2bpf__destroy(tc_skel);
+ tailcall_freplace__destroy(freplace_skel);
+}
+
void test_tailcalls(void)
{
if (test__start_subtest("tailcall_1"))
@@ -1543,4 +1604,6 @@ void test_tailcalls(void)
test_tailcall_bpf2bpf_hierarchy_fentry_entry();
test_tailcall_bpf2bpf_hierarchy_2();
test_tailcall_bpf2bpf_hierarchy_3();
+ if (test__start_subtest("tailcall_freplace"))
+ test_tailcall_freplace();
}
diff --git a/tools/testing/selftests/bpf/progs/tailcall_freplace.c b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
new file mode 100644
index 0000000000000..2966efc06ae8f
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+ __uint(max_entries, 1);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u32));
+} jmp_table SEC(".maps");
+
+int count = 0;
+
+SEC("freplace")
+int entry_freplace(struct __sk_buff *skb)
+{
+ count++;
+
remove empty line here.
+ bpf_tail_call_static(skb, &jmp_table, 0);
+
remove empty line here.
+ return count;
+}
+
+char __license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
new file mode 100644
index 0000000000000..980bb810b481c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+__noinline
+int subprog(struct __sk_buff *skb)
+{
+ volatile int ret = 1;
+
remove empty line here.
+ asm volatile (""::"r+"(ret));
remove above 'volatile' key word and replace asm volatile with __sink(ret).
+ return ret;
+}
+
+SEC("tc")
+int entry_tc(struct __sk_buff *skb)
+{
+ return subprog(skb);
+}
+
+char __license[] SEC("license") = "GPL";
