On 7/24/24 5:32 PM, 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>
---
.../selftests/bpf/prog_tests/tailcalls.c | 76 ++++++++++++++++++-
.../selftests/bpf/progs/tailcall_freplace.c | 33 ++++++++
.../testing/selftests/bpf/progs/tc_bpf2bpf.c | 23 ++++++
3 files changed, 131 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..f1145601c0005 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 +1496,77 @@ 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 to PROG_ARRAY map.
update the prog_array map.
+ */
+static void test_tailcall_freplace(void)
+{
+ struct tailcall_freplace *fr_skel = NULL;
+ struct tc_bpf2bpf *tc_skel = NULL;
+ struct bpf_link *fr_link = 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,
+ );
+
+ fr_skel = tailcall_freplace__open();
+ if (!ASSERT_OK_PTR(fr_skel, "open fr_skel"))
if (!ASSERT_OK_PTR(fr_skel, "open fr_skel"))
==>
if (!ASSERT_OK_PTR(fr_skel, "tailcall_freplace__open"))
Similar for below other ASSERT_* macros.
+ goto out;
Let us just do 'return' here.
+
+ tc_skel = tc_bpf2bpf__open_and_load();
+ if (!ASSERT_OK_PTR(tc_skel, "open tc_skel"))
+ goto out;
+
+ prog_fd = bpf_program__fd(tc_skel->progs.entry);
+ if (!ASSERT_GE(prog_fd, 0, "tc_skel entry prog_id"))
+ goto out;
ASSERT_GE is not necessary, prog_fd should already be valid.
+
+ err = bpf_program__set_attach_target(fr_skel->progs.entry,
+ prog_fd, "subprog");
+ if (!ASSERT_OK(err, "set_attach_target"))
+ goto out;
+
+ err = tailcall_freplace__load(fr_skel);
+ if (!ASSERT_OK(err, "load fr_skel"))
+ goto out;
+
+ fr_link = bpf_program__attach_freplace(fr_skel->progs.entry,
+ prog_fd, "subprog");
+ if (!ASSERT_OK_PTR(fr_link, "attach_freplace"))
+ goto out;
+
+ prog_fd = bpf_program__fd(fr_skel->progs.entry);
+ if (!ASSERT_GE(prog_fd, 0, "fr_skel entry prog_fd"))
+ goto out;
prog_fd is valid here. No need ASSERT_GE.
+
+ map_fd = bpf_map__fd(fr_skel->maps.jmp_table);
+ if (!ASSERT_GE(map_fd, 0, "fr_skel jmp_table map_fd"))
+ goto out;
map_fd is valid. No need ASSERT_GE.
+
+ 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);
+ if (!ASSERT_GE(prog_fd, 0, "prog_fd"))
+ goto out;
prog_fd is valid here.
+
+ 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(fr_link);
+ tc_bpf2bpf__destroy(tc_skel);
+ tailcall_freplace__destroy(fr_skel);
+}
+
void test_tailcalls(void)
{
if (test__start_subtest("tailcall_1"))
@@ -1543,4 +1615,6 @@ 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..80b5fa386ed9c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_legacy.h"
bpf_legacy.h is not needed.
+
+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;
+
+__noinline
+int subprog(struct __sk_buff *skb)
+{
+ count++;
+
+ bpf_tail_call_static(skb, &jmp_table, 0);
+
+ return count;
+}
subprog() can be inlined into entry(). This
can avoid confusing vs. tc_bpf2bpf.c.
Better if you can differentiate two 'entry()' function
names, e.g., entry_freplace(), entry_tc(), it can make
it easy for people to understand your change in tailcalls.c.
+
+SEC("freplace")
+int entry(struct __sk_buff *skb)
+{
+ return subprog(skb);
+}
+
+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..4810961554585
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_legacy.h"
+
+__noinline
+int subprog(struct __sk_buff *skb)
+{
+ volatile int ret = 1;
+
+ asm volatile (""::"r+"(ret));
+ return ret;
+}
+
+SEC("tc")
+int entry(struct __sk_buff *skb)
+{
+ return subprog(skb);
+}
+
+char __license[] SEC("license") = "GPL";
+
