[PATCH v2 bpf-next 03/13] selftests/bpf: Update linked_list tests for non-owning ref semantics

Dave Marchevsky
2022-12-17T08:25:27Z

Current linked_list semantics for release_on_unlock node refs are almost
exactly the same as newly-introduced "non-owning reference" concept. The
only difference: writes to a release_on_unlock node ref are not allowed,
while writes to non-owning reference pointees are.

As a result the linked_list "write after push" failure tests are no
longer scenarios that should fail.

The test##_missing_lock_##op and test##_incorrect_lock_##op
macro-generated failure tests need to have a valid node argument in
order to have the same error output as before. Otherwise verification
will fail early and the expected error output won't be seen.

Some other tests have minor changes in error output, but fail for the
same reason.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
---
.../selftests/bpf/prog_tests/linked_list.c | 10 +-
.../testing/selftests/bpf/progs/linked_list.c | 2 +-
.../selftests/bpf/progs/linked_list_fail.c | 100 +++++++++++-------
3 files changed, 68 insertions(+), 44 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c
index 9a7d4c47af63..a8091a0c0831 100644
--- a/tools/testing/selftests/bpf/prog_tests/linked_list.c
+++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c
@@ -78,18 +78,18 @@ static struct {
{ "direct_write_head", "direct access to bpf_list_head is disallowed" },
{ "direct_read_node", "direct access to bpf_list_node is disallowed" },
{ "direct_write_node", "direct access to bpf_list_node is disallowed" },
- { "write_after_push_front", "only read is supported" },
- { "write_after_push_back", "only read is supported" },
{ "use_after_unlock_push_front", "invalid mem access 'scalar'" },
{ "use_after_unlock_push_back", "invalid mem access 'scalar'" },
- { "double_push_front", "arg#1 expected pointer to allocated object" },
- { "double_push_back", "arg#1 expected pointer to allocated object" },
+ { "double_push_front",
+ "release kernel function bpf_list_push_front expects refcounted PTR_TO_BTF_ID" },
+ { "double_push_back",
+ "release kernel function bpf_list_push_back expects refcounted PTR_TO_BTF_ID" },
{ "no_node_value_type", "bpf_list_node not found at offset=0" },
{ "incorrect_value_type",
"operation on bpf_list_head expects arg#1 bpf_list_node at offset=0 in struct foo, "
"but arg is at offset=0 in struct bar" },
{ "incorrect_node_var_off", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" },
- { "incorrect_node_off1", "bpf_list_node not found at offset=1" },
+ { "incorrect_node_off1", "No graph node or root found at R2 type:foo off:1" },
{ "incorrect_node_off2", "arg#1 offset=40, but expected bpf_list_node at offset=0 in struct foo" },
{ "no_head_type", "bpf_list_head not found at offset=0" },
{ "incorrect_head_var_off1", "R1 doesn't have constant offset" },
diff --git a/tools/testing/selftests/bpf/progs/linked_list.c b/tools/testing/selftests/bpf/progs/linked_list.c
index 4ad88da5cda2..4fa4a9b01bde 100644
--- a/tools/testing/selftests/bpf/progs/linked_list.c
+++ b/tools/testing/selftests/bpf/progs/linked_list.c
@@ -260,7 +260,7 @@ int test_list_push_pop_multiple(struct bpf_spin_lock *lock, struct bpf_list_head
{
int ret;

- ret = list_push_pop_multiple(lock ,head, false);
+ ret = list_push_pop_multiple(lock, head, false);
if (ret)
return ret;
return list_push_pop_multiple(lock, head, true);
diff --git a/tools/testing/selftests/bpf/progs/linked_list_fail.c b/tools/testing/selftests/bpf/progs/linked_list_fail.c
index 1d9017240e19..69cdc07cba13 100644
--- a/tools/testing/selftests/bpf/progs/linked_list_fail.c
+++ b/tools/testing/selftests/bpf/progs/linked_list_fail.c
@@ -54,28 +54,44 @@
return 0; \
}

-CHECK(kptr, push_front, &f->head);
-CHECK(kptr, push_back, &f->head);
CHECK(kptr, pop_front, &f->head);
CHECK(kptr, pop_back, &f->head);

-CHECK(global, push_front, &ghead);
-CHECK(global, push_back, &ghead);
CHECK(global, pop_front, &ghead);
CHECK(global, pop_back, &ghead);

-CHECK(map, push_front, &v->head);
-CHECK(map, push_back, &v->head);
CHECK(map, pop_front, &v->head);
CHECK(map, pop_back, &v->head);

-CHECK(inner_map, push_front, &iv->head);
-CHECK(inner_map, push_back, &iv->head);
CHECK(inner_map, pop_front, &iv->head);
CHECK(inner_map, pop_back, &iv->head);

#undef CHECK

+#define CHECK(test, op, hexpr, nexpr) \
+ SEC("?tc") \
+ int test##_missing_lock_##op(void *ctx) \
+ { \
+ INIT; \
+ void (*p)(void *, void *) = (void *)&bpf_list_##op; \
+ p(hexpr, nexpr); \
+ return 0; \
+ }
+
+CHECK(kptr, push_front, &f->head, b);
+CHECK(kptr, push_back, &f->head, b);
+
+CHECK(global, push_front, &ghead, f);
+CHECK(global, push_back, &ghead, f);
+
+CHECK(map, push_front, &v->head, f);
+CHECK(map, push_back, &v->head, f);
+
+CHECK(inner_map, push_front, &iv->head, f);
+CHECK(inner_map, push_back, &iv->head, f);
+
+#undef CHECK
+
#define CHECK(test, op, lexpr, hexpr) \
SEC("?tc") \
int test##_incorrect_lock_##op(void *ctx) \
@@ -108,11 +124,47 @@ CHECK(inner_map, pop_back, &iv->head);
CHECK(inner_map_global, op, &iv->lock, &ghead); \
CHECK(inner_map_map, op, &iv->lock, &v->head);

-CHECK_OP(push_front);
-CHECK_OP(push_back);
CHECK_OP(pop_front);
CHECK_OP(pop_back);

+#undef CHECK
+#undef CHECK_OP
+
+#define CHECK(test, op, lexpr, hexpr, nexpr) \
+ SEC("?tc") \
+ int test##_incorrect_lock_##op(void *ctx) \
+ { \
+ INIT; \
+ void (*p)(void *, void*) = (void *)&bpf_list_##op; \
+ bpf_spin_lock(lexpr); \
+ p(hexpr, nexpr); \
+ return 0; \
+ }
+
+#define CHECK_OP(op) \
+ CHECK(kptr_kptr, op, &f1->lock, &f2->head, b); \
+ CHECK(kptr_global, op, &f1->lock, &ghead, f); \
+ CHECK(kptr_map, op, &f1->lock, &v->head, f); \
+ CHECK(kptr_inner_map, op, &f1->lock, &iv->head, f); \
+ \
+ CHECK(global_global, op, &glock2, &ghead, f); \
+ CHECK(global_kptr, op, &glock, &f1->head, b); \
+ CHECK(global_map, op, &glock, &v->head, f); \
+ CHECK(global_inner_map, op, &glock, &iv->head, f); \
+ \
+ CHECK(map_map, op, &v->lock, &v2->head, f); \
+ CHECK(map_kptr, op, &v->lock, &f2->head, b); \
+ CHECK(map_global, op, &v->lock, &ghead, f); \
+ CHECK(map_inner_map, op, &v->lock, &iv->head, f); \
+ \
+ CHECK(inner_map_inner_map, op, &iv->lock, &iv2->head, f); \
+ CHECK(inner_map_kptr, op, &iv->lock, &f2->head, b); \
+ CHECK(inner_map_global, op, &iv->lock, &ghead, f); \
+ CHECK(inner_map_map, op, &iv->lock, &v->head, f);
+
+CHECK_OP(push_front);
+CHECK_OP(push_back);
+
#undef CHECK
#undef CHECK_OP
#undef INIT
@@ -303,34 +355,6 @@ int direct_write_node(void *ctx)
return 0;
}

-static __always_inline
-int write_after_op(void (*push_op)(void *head, void *node))
-{
- struct foo *f;
-
- f = bpf_obj_new(typeof(*f));
- if (!f)
- return 0;
- bpf_spin_lock(&glock);
- push_op(&ghead, &f->node);
- f->data = 42;
- bpf_spin_unlock(&glock);
-
- return 0;
-}
-
-SEC("?tc")
-int write_after_push_front(void *ctx)
-{
- return write_after_op((void *)bpf_list_push_front);
-}
-
-SEC("?tc")
-int write_after_push_back(void *ctx)
-{
- return write_after_op((void *)bpf_list_push_back);
-}
-
static __always_inline
int use_after_unlock(void (*op)(void *head, void *node))
{
--
2.30.2