Multiple test cases already fail if you add a type whose size is
different between userspace and bpf. That said, let's also add an
explicit test that ensures mis-sized reads/writes do not actually
happen. This test case fails before this patch series and passes after:
test_skeleton:FAIL:writes and reads match size unexpected writes
and reads match size: actual 3735928559 != expected 8030895855
test_skeleton:FAIL:skeleton uses underlying type unexpected
skeleton uses underlying type: actual 8 != expected 4
Signed-off-by: Delyan Kratunov <delyank@xxxxxx>
---
tools/testing/selftests/bpf/prog_tests/skeleton.c | 6 ++++++
tools/testing/selftests/bpf/progs/test_skeleton.c | 8 ++++++++
2 files changed, 14 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/skeleton.c b/tools/testing/selftests/bpf/prog_tests/skeleton.c
index 9894e1b39211..bc07da929566 100644
--- a/tools/testing/selftests/bpf/prog_tests/skeleton.c
+++ b/tools/testing/selftests/bpf/prog_tests/skeleton.c
@@ -97,6 +97,9 @@ void test_skeleton(void)
skel->data_read_mostly->read_mostly_var = 123;
+ /* validate apparent 64-bit value is actually 32-bit */
+ skel->data->intest64 = (typeof(skel->data->intest64)) 0xdeadbeefdeadbeefULL;
+
err = test_skeleton__attach(skel);
if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
goto cleanup;
@@ -126,6 +129,9 @@ void test_skeleton(void)
ASSERT_OK_PTR(elf_bytes, "elf_bytes");
ASSERT_GE(elf_bytes_sz, 0, "elf_bytes_sz");
+ ASSERT_EQ(skel->data->outtest64, skel->data->intest64, "writes and reads match size");
+ ASSERT_EQ(sizeof(skel->data->intest64), sizeof(u32), "skeleton uses underlying type");
+
cleanup:
test_skeleton__destroy(skel);
}
diff --git a/tools/testing/selftests/bpf/progs/test_skeleton.c b/tools/testing/selftests/bpf/progs/test_skeleton.c
index 1b1187d2967b..fd1f4910cf42 100644
--- a/tools/testing/selftests/bpf/progs/test_skeleton.c
+++ b/tools/testing/selftests/bpf/progs/test_skeleton.c
@@ -16,6 +16,13 @@ struct s {
int in1 = -1;
long long in2 = -1;
+/* declare the int64_t type to actually be 32-bit to ensure the skeleton
+ * uses actual sizes and doesn't just copy the type name
+ */
+typedef __s32 int64_t;
+int64_t intest64 = -1;
+int64_t outtest64 = -1;
+
/* .bss section */
char in3 = '\0';
long long in4 __attribute__((aligned(64))) = 0;
@@ -62,6 +69,7 @@ int handler(const void *ctx)
out4 = in4;
out5 = in5;
out6 = in.in6;
+ outtest64 = intest64;
bpf_syscall = CONFIG_BPF_SYSCALL;
kern_ver = LINUX_KERNEL_VERSION;
--
2.34.1
