1 files changed, 94 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_global_map_resize.c b/tools/testing/selftests/bpf/progs/test_global_map_resize.c
new file mode 100644
index 000000000000..ee65bad0436d
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_global_map_resize.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+/* rodata section */
+const volatile pid_t pid;
+const volatile size_t bss_array_len;
+const volatile size_t data_array_len;
+
+/* bss section */
+int sum = 0;
+int array[1];
+
+/* custom data section */
+int my_array[1] SEC(".data.custom");
+
+/* custom data section which should NOT be resizable,
+ * since it contains a single var which is not an array
+ */
+int my_int SEC(".data.non_array");
+
+/* custom data section which should NOT be resizable,
+ * since its last var is not an array
+ */
+int my_array_first[1] SEC(".data.array_not_last");
+int my_int_last SEC(".data.array_not_last");
+
+int percpu_arr[1] SEC(".data.percpu_arr");
+
+/* at least one extern is included, to ensure that a specific
+ * regression is tested whereby resizing resulted in a free-after-use
+ * bug after type information is invalidated by the resize operation.
+ *
+ * There isn't a particularly good API to test for this specific condition,
+ * but by having externs for the resizing tests it will cover this path.
+ */
+extern int LINUX_KERNEL_VERSION __kconfig;
+long version_sink;
+
+SEC("tp/syscalls/sys_enter_getpid")
+int bss_array_sum(void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+	/* this will be zero, we just rely on verifier not rejecting this */
+	sum = percpu_arr[bpf_get_smp_processor_id()];
+
+	for (size_t i = 0; i < bss_array_len; ++i)
+		sum += array[i];
+
+	/* see above; ensure this is not optimized out */
+	version_sink = LINUX_KERNEL_VERSION;
+
+	return 0;
+}
+
+SEC("tp/syscalls/sys_enter_getuid")
+int data_array_sum(void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+	/* this will be zero, we just rely on verifier not rejecting this */
+	sum = percpu_arr[bpf_get_smp_processor_id()];
+
+	for (size_t i = 0; i < data_array_len; ++i)
+		sum += my_array[i];
+
+	/* see above; ensure this is not optimized out */
+	version_sink = LINUX_KERNEL_VERSION;
+
+	return 0;
+}
+
+SEC("struct_ops/test_1")
+int BPF_PROG(test_1)
+{
+	return 0;
+}
+
+struct bpf_testmod_ops {
+	int (*test_1)(void);
+};
+
+SEC(".struct_ops.link")
+struct bpf_testmod_ops st_ops_resize = {
+	.test_1 = (void *)test_1
+};