selftests/bpf: validate .bss section bigger than 8MB is possible now

Add a simple big 16MB array and validate access to the very last byte of
it to make sure that kernel supports > KMALLOC_MAX_SIZE value_size for
BPF array maps (which are backing .bss in this case).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220715053146.1291891-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/skeleton.c b/tools/testing/selftests/bpf/prog_tests/skeleton.c
index 180afd632f4caa06fe9475fd7c83f853e965c9de..99dac5292b41a37e69a796984d2fa07e35cfedc3 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/skeleton.c
+++ b/tools/testing/selftests/bpf/prog_tests/skeleton.c
@@ -122,6 +122,8 @@ void test_skeleton(void)
 
        ASSERT_EQ(skel->bss->out_mostly_var, 123, "out_mostly_var");
 
+       ASSERT_EQ(bss->huge_arr[ARRAY_SIZE(bss->huge_arr) - 1], 123, "huge_arr");
+
        elf_bytes = test_skeleton__elf_bytes(&elf_bytes_sz);
        ASSERT_OK_PTR(elf_bytes, "elf_bytes");
        ASSERT_GE(elf_bytes_sz, 0, "elf_bytes_sz");

diff --git a/tools/testing/selftests/bpf/progs/test_skeleton.c b/tools/testing/selftests/bpf/progs/test_skeleton.c
index 1b1187d2967bd468d7ff0ebe6d2ebe81ef911a8a..1a4e93f6d9df9474219f8cf4befe52c47142aee7 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_skeleton.c
+++ b/tools/testing/selftests/bpf/progs/test_skeleton.c
@@ -51,6 +51,8 @@ int out_dynarr[4] SEC(".data.dyn") = { 1, 2, 3, 4 };
 int read_mostly_var __read_mostly;
 int out_mostly_var;
 
+char huge_arr[16 * 1024 * 1024];
+
 SEC("raw_tp/sys_enter")
 int handler(const void *ctx)
 {
@@ -71,6 +73,8 @@ int handler(const void *ctx)
 
        out_mostly_var = read_mostly_var;
 
+       huge_arr[sizeof(huge_arr) - 1] = 123;
+
        return 0;
 }