selftests/bpf: Add update_elem failure test for task storage uptr

This patch test the following failures in syscall update_elem
1. The first update_elem(BPF_F_LOCK) should be EOPNOTSUPP. syscall.c takes
   care of unpinning the uptr.
2. The second update_elem(BPF_EXIST) fails. syscall.c takes care of
   unpinning the uptr.
3. The forth update_elem(BPF_NOEXIST) fails. bpf_local_storage_update
   takes care of unpinning the uptr.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20241023234759.860539-11-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 45 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
index b7af0921b3da..e985665efe7a 100644
--- a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
+++ b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
@@ -17,6 +17,7 @@
 #include "task_storage_nodeadlock.skel.h"
 #include "uptr_test_common.h"
 #include "task_ls_uptr.skel.h"
+#include "uptr_update_failure.skel.h"
 
 static void test_sys_enter_exit(void)
 {
@@ -408,6 +409,48 @@ out:
 	munmap(mem, page_size * 2);
 }
 
+static void test_uptr_update_failure(void)
+{
+	struct value_lock_type value = {};
+	struct uptr_update_failure *skel;
+	int err, task_fd, map_fd;
+
+	task_fd = sys_pidfd_open(getpid(), 0);
+	if (!ASSERT_OK_FD(task_fd, "task_fd"))
+		return;
+
+	skel = uptr_update_failure__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		goto out;
+
+	map_fd = bpf_map__fd(skel->maps.datamap);
+
+	value.udata = &udata;
+	err = bpf_map_update_elem(map_fd, &task_fd, &value, BPF_F_LOCK);
+	if (!ASSERT_ERR(err, "update_elem(udata, BPF_F_LOCK)"))
+		goto out;
+	ASSERT_EQ(errno, EOPNOTSUPP, "errno");
+
+	err = bpf_map_update_elem(map_fd, &task_fd, &value, BPF_EXIST);
+	if (!ASSERT_ERR(err, "update_elem(udata, BPF_EXIST)"))
+		goto out;
+	ASSERT_EQ(errno, ENOENT, "errno");
+
+	err = bpf_map_update_elem(map_fd, &task_fd, &value, BPF_NOEXIST);
+	if (!ASSERT_OK(err, "update_elem(udata, BPF_NOEXIST)"))
+		goto out;
+
+	value.udata = &udata2;
+	err = bpf_map_update_elem(map_fd, &task_fd, &value, BPF_NOEXIST);
+	if (!ASSERT_ERR(err, "update_elem(udata2, BPF_NOEXIST)"))
+		goto out;
+	ASSERT_EQ(errno, EEXIST, "errno");
+
+out:
+	uptr_update_failure__destroy(skel);
+	close(task_fd);
+}
+
 void test_task_local_storage(void)
 {
 	if (test__start_subtest("sys_enter_exit"))
@@ -422,4 +465,6 @@ void test_task_local_storage(void)
 		test_uptr_basic();
 	if (test__start_subtest("uptr_across_pages"))
 		test_uptr_across_pages();
+	if (test__start_subtest("uptr_update_failure"))
+		test_uptr_update_failure();
 }