Maps of per-cpu type have their value element size adjusted to 8 if it
is specified smaller during various map operations.
This makes test_maps as a 32-bit binary fail, in fact the kernel
writes past the end of the value's array on the user's stack.
To be quite honest, I think the kernel should reject creation of a
per-cpu map that doesn't have a value size of at least 8 if that's
what the kernel is going to silently adjust to later.
If the user passed something smaller, it is a sizeof() calcualtion
based upon the type they will actually use (just like in this testcase
code) in later calls to the map operations.
Signed-off-by: David S. Miller <da...@davemloft.net>
diff --git a/tools/testing/selftests/bpf/test_maps.c
b/tools/testing/selftests/bpf/test_maps.c
index a0aa200..20f1871 100644
--- a/tools/testing/selftests/bpf/test_maps.c
+++ b/tools/testing/selftests/bpf/test_maps.c
@@ -282,7 +282,7 @@ static void test_arraymap_percpu(int task, void *data)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
int key, next_key, fd, i;
- long values[nr_cpus];
+ long long values[nr_cpus];
fd = bpf_create_map(BPF_MAP_TYPE_PERCPU_ARRAY, sizeof(key),
sizeof(values[0]), 2, 0);
@@ -340,7 +340,7 @@ static void test_arraymap_percpu_many_keys(void)
* allocator more than anything else
*/
unsigned int nr_keys = 2000;
- long values[nr_cpus];
+ long long values[nr_cpus];
int key, fd, i;
fd = bpf_create_map(BPF_MAP_TYPE_PERCPU_ARRAY, sizeof(key),
