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>

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 b7af092..e985665 100644 (file)
--- 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();
 }

diff --git a/tools/testing/selftests/bpf/progs/uptr_update_failure.c b/tools/testing/selftests/bpf/progs/uptr_update_failure.c
new file mode 100644 (file)
index 0000000..86c3bb9
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/uptr_update_failure.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include "uptr_test_common.h"
+
+struct {
+       __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
+       __uint(map_flags, BPF_F_NO_PREALLOC);
+       __type(key, int);
+       __type(value, struct value_lock_type);
+} datamap SEC(".maps");
+
+/* load test only. not used */
+SEC("syscall")
+int not_used(void *ctx)
+{
+       struct value_lock_type *ptr;
+       struct task_struct *task;
+       struct user_data *udata;
+
+       task = bpf_get_current_task_btf();
+       ptr = bpf_task_storage_get(&datamap, task, 0, 0);
+       if (!ptr)
+               return 0;
+
+       bpf_spin_lock(&ptr->lock);
+
+       udata = ptr->udata;
+       if (!udata) {
+               bpf_spin_unlock(&ptr->lock);
+               return 0;
+       }
+       udata->result = MAGIC_VALUE + udata->a + udata->b;
+
+       bpf_spin_unlock(&ptr->lock);
+
+       return 0;
+}
+
+char _license[] SEC("license") = "GPL";

diff --git a/tools/testing/selftests/bpf/uptr_test_common.h b/tools/testing/selftests/bpf/uptr_test_common.h
index feb4117..45c00c8 100644 (file)
--- a/tools/testing/selftests/bpf/uptr_test_common.h
+++ b/tools/testing/selftests/bpf/uptr_test_common.h
@@ -32,4 +32,9 @@ struct value_type {
        struct nested_udata nested;
 };
 
+struct value_lock_type {
+       struct user_data __uptr *udata;
+       struct bpf_spin_lock lock;
+};
+
 #endif