Verify whether a user space program is informed through epoll with EPOLLHUP
when a struct_ops object is detached.
Signed-off-by: Kui-Feng Lee <thinker.li@xxxxxxxxx>
---
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 13 +++++
.../bpf/bpf_testmod/bpf_testmod_kfunc.h | 1 +
.../bpf/prog_tests/test_struct_ops_module.c | 57 +++++++++++++++++++
.../selftests/bpf/progs/struct_ops_detach.c | 31 ++++++++++
4 files changed, 102 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_detach.c
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index e24a18bfee14..c89a6414c69f 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -10,6 +10,7 @@
#include <linux/percpu-defs.h>
#include <linux/sysfs.h>
#include <linux/tracepoint.h>
+#include <linux/workqueue.h>
#include "bpf_testmod.h"
#include "bpf_testmod_kfunc.h"
@@ -498,6 +499,9 @@ __bpf_kfunc void bpf_kfunc_call_test_sleepable(void)
{
}
+static DEFINE_MUTEX(detach_mutex);
+static struct bpf_link *link_to_detach;
+
BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -577,11 +581,20 @@ static int bpf_dummy_reg(void *kdata, struct bpf_link *link)
if (ops->test_2)
ops->test_2(4, ops->data);
+ mutex_lock(&detach_mutex);
+ if (!link_to_detach)
+ link_to_detach = link;
+ mutex_unlock(&detach_mutex);
+
return 0;
}
static void bpf_dummy_unreg(void *kdata, struct bpf_link *link)
{
+ mutex_lock(&detach_mutex);
+ if (link == link_to_detach)
+ link_to_detach = NULL;
+ mutex_unlock(&detach_mutex);
}
static int bpf_testmod_test_1(void)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
index ce5cd763561c..9f9b60880fd3 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
@@ -105,6 +105,7 @@ void bpf_kfunc_call_test_fail1(struct prog_test_fail1 *p);
void bpf_kfunc_call_test_fail2(struct prog_test_fail2 *p);
void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p);
void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len);
+int bpf_dummy_do_link_detach(void) __ksym;
void bpf_kfunc_common_test(void) __ksym;
#endif /* _BPF_TESTMOD_KFUNC_H */
diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
index bd39586abd5a..f39455b81664 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -2,8 +2,12 @@
/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
#include <test_progs.h>
#include <time.h>
+#include <network_helpers.h>
+
+#include <sys/epoll.h>
#include "struct_ops_module.skel.h"
+#include "struct_ops_detach.skel.h"
static void check_map_info(struct bpf_map_info *info)
{
@@ -174,6 +178,57 @@ static void test_struct_ops_incompatible(void)
struct_ops_module__destroy(skel);
}
+/* Detach a link from a user space program */
+static void test_detach_link(void)
+{
+ struct epoll_event ev, events[2];
+ struct struct_ops_detach *skel;
+ struct bpf_link *link = NULL;
+ int fd, epollfd = -1, nfds;
+ int err;
+
+ skel = struct_ops_detach__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "struct_ops_detach__open_and_load"))
+ return;
+
+ link = bpf_map__attach_struct_ops(skel->maps.testmod_do_detach);
+ if (!ASSERT_OK_PTR(link, "attach_struct_ops"))
+ goto cleanup;
+
+ fd = bpf_link__fd(link);
+ if (!ASSERT_GE(fd, 0, "link_fd"))
+ goto cleanup;
+
+ epollfd = epoll_create1(0);
+ if (!ASSERT_GE(epollfd, 0, "epoll_create1"))
+ goto cleanup;
+
+ ev.events = EPOLLHUP;
+ ev.data.fd = fd;
+ err = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
+ if (!ASSERT_OK(err, "epoll_ctl"))
+ goto cleanup;
+
+ err = bpf_link__detach(link);
+ if (!ASSERT_OK(err, "detach_link"))
+ goto cleanup;
+
+ /* Wait for EPOLLHUP */
+ nfds = epoll_wait(epollfd, events, 2, 500);
+ if (!ASSERT_EQ(nfds, 1, "epoll_wait"))
+ goto cleanup;
+
+ if (!ASSERT_EQ(events[0].data.fd, fd, "epoll_wait_fd"))
+ goto cleanup;
+ if (!ASSERT_TRUE(events[0].events & EPOLLHUP, "events[0].events"))
+ goto cleanup;
+
+cleanup:
+ close(epollfd);
+ bpf_link__destroy(link);
+ struct_ops_detach__destroy(skel);
+}
+
void serial_test_struct_ops_module(void)
{
if (test__start_subtest("test_struct_ops_load"))
@@ -182,5 +237,7 @@ void serial_test_struct_ops_module(void)
test_struct_ops_not_zeroed();
if (test__start_subtest("test_struct_ops_incompatible"))
test_struct_ops_incompatible();
+ if (test__start_subtest("test_detach_link"))
+ test_detach_link();
}
diff --git a/tools/testing/selftests/bpf/progs/struct_ops_detach.c b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
new file mode 100644
index 000000000000..aeb355b3bea3
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "../bpf_testmod/bpf_testmod.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
+
+char _license[] SEC("license") = "GPL";
+
+int test_1_result = 0;
+int test_2_result = 0;
+
+SEC("struct_ops/test_1")
+int BPF_PROG(test_1)
+{
+ test_1_result = 0xdeadbeef;
+ return 0;
+}
+
+SEC("struct_ops/test_2")
+void BPF_PROG(test_2, int a, int b)
+{
+ test_2_result = a + b;
+}
+
+SEC(".struct_ops.link")
+struct bpf_testmod_ops testmod_do_detach = {
+ .test_1 = (void *)test_1,
+ .test_2 = (void *)test_2,
+};
--
2.34.1
