This adds a simple test for inserting an XDP program into a cpumap that is
"owned" by an XDP program that was loaded as PROG_TYPE_EXT (as libxdp
does). Prior to the kernel fix this would fail because the map type
ownership would be set to PROG_TYPE_EXT instead of being resolved to
PROG_TYPE_XDP.
v5:
- Fix a few nits from Andrii, add his ACK
v4:
- Use skeletons for selftest
v3:
- Update comment to better explain the cause
- Add Yonghong's ACK
Acked-by: Yonghong Song <yhs@xxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
---
.../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 48 +++++++++++++++++++
.../selftests/bpf/progs/freplace_progmap.c | 24 ++++++++++
2 files changed, 72 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/freplace_progmap.c
diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
index d1e32e792536..20f5fa0fcec9 100644
--- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
@@ -4,6 +4,8 @@
#include <network_helpers.h>
#include <bpf/btf.h>
#include "bind4_prog.skel.h"
+#include "freplace_progmap.skel.h"
+#include "xdp_dummy.skel.h"
typedef int (*test_cb)(struct bpf_object *obj);
@@ -500,6 +502,50 @@ static void test_fentry_to_cgroup_bpf(void)
bind4_prog__destroy(skel);
}
+static void test_func_replace_progmap(void)
+{
+ struct bpf_cpumap_val value = { .qsize = 1 };
+ struct freplace_progmap *skel = NULL;
+ struct xdp_dummy *tgt_skel = NULL;
+ __u32 key = 0;
+ int err;
+
+ skel = freplace_progmap__open();
+ if (!ASSERT_OK_PTR(skel, "prog_open"))
+ return;
+
+ tgt_skel = xdp_dummy__open_and_load();
+ if (!ASSERT_OK_PTR(tgt_skel, "tgt_prog_load"))
+ goto out;
+
+ err = bpf_program__set_attach_target(skel->progs.xdp_cpumap_prog,
+ bpf_program__fd(tgt_skel->progs.xdp_dummy_prog),
+ "xdp_dummy_prog");
+ if (!ASSERT_OK(err, "set_attach_target"))
+ goto out;
+
+ err = freplace_progmap__load(skel);
+ if (!ASSERT_OK(err, "obj_load"))
+ goto out;
+
+ /* Prior to fixing the kernel, loading the PROG_TYPE_EXT 'redirect'
+ * program above will cause the map owner type of 'cpumap' to be set to
+ * PROG_TYPE_EXT. This in turn will cause the bpf_map_update_elem()
+ * below to fail, because the program we are inserting into the map is
+ * of PROG_TYPE_XDP. After fixing the kernel, the initial ownership will
+ * be correctly resolved to the *target* of the PROG_TYPE_EXT program
+ * (i.e., PROG_TYPE_XDP) and the map update will succeed.
+ */
+ value.bpf_prog.fd = bpf_program__fd(skel->progs.xdp_drop_prog);
+ err = bpf_map_update_elem(bpf_map__fd(skel->maps.cpu_map),
+ &key, &value, 0);
+ ASSERT_OK(err, "map_update");
+
+out:
+ xdp_dummy__destroy(tgt_skel);
+ freplace_progmap__destroy(skel);
+}
+
/* NOTE: affect other tests, must run in serial mode */
void serial_test_fexit_bpf2bpf(void)
{
@@ -525,4 +571,6 @@ void serial_test_fexit_bpf2bpf(void)
test_func_replace_global_func();
if (test__start_subtest("fentry_to_cgroup_bpf"))
test_fentry_to_cgroup_bpf();
+ if (test__start_subtest("func_replace_progmap"))
+ test_func_replace_progmap();
}
diff --git a/tools/testing/selftests/bpf/progs/freplace_progmap.c b/tools/testing/selftests/bpf/progs/freplace_progmap.c
new file mode 100644
index 000000000000..81b56b9aa7d6
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/freplace_progmap.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_CPUMAP);
+ __type(key, __u32);
+ __type(value, struct bpf_cpumap_val);
+ __uint(max_entries, 1);
+} cpu_map SEC(".maps");
+
+SEC("xdp/cpumap")
+int xdp_drop_prog(struct xdp_md *ctx)
+{
+ return XDP_DROP;
+}
+
+SEC("freplace")
+int xdp_cpumap_prog(struct xdp_md *ctx)
+{
+ return bpf_redirect_map(&cpu_map, 0, XDP_PASS);
+}
+
+char _license[] SEC("license") = "GPL";
--
2.38.1
