[PATCH bpf-next 16/18] selftests/bpf: add checks for bpf_wq_set_callback()

From: Benjamin Tissoires
Date: Tue Apr 16 2024 - 10:16:02 EST


We assign the callback and set everything up.
The actual tests of these callbacks will be done when bpf_wq_start() is
available.

Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx>
---
tools/testing/selftests/bpf/bpf_experimental.h | 5 +
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 5 +
.../selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h | 1 +
tools/testing/selftests/bpf/progs/wq.c | 47 +++++++--
tools/testing/selftests/bpf/progs/wq_failures.c | 115 +++++++++++++++++++++
5 files changed, 165 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 6af6f2a43e6d..272604f9c4a5 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -471,4 +471,9 @@ extern struct cgroup_subsys_state *bpf_iter_css_next(struct bpf_iter_css *it) __
extern void bpf_iter_css_destroy(struct bpf_iter_css *it) __weak __ksym;

extern int bpf_wq_init(struct bpf_wq *wq, void *map, unsigned int flags) __weak __ksym;
+extern int bpf_wq_set_callback_impl(struct bpf_wq *wq,
+ int (callback_fn)(void *map, int *key, struct bpf_wq *wq),
+ unsigned int flags__k, void *aux__ign) __ksym;
+#define bpf_wq_set_callback(timer, cb, flags) \
+ bpf_wq_set_callback_impl(timer, cb, flags, NULL)
#endif
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 39ad96a18123..eb2b78552ca2 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -494,6 +494,10 @@ __bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused
return arg;
}

+__bpf_kfunc void bpf_kfunc_call_test_sleepable(void)
+{
+}
+
BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -520,6 +524,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS | KF_RCU)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_sleepable, KF_SLEEPABLE)
BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)

static int bpf_testmod_ops_init(struct btf *btf)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
index 7c664dd61059..ce5cd763561c 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
@@ -96,6 +96,7 @@ void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym;
void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;

void bpf_kfunc_call_test_destructive(void) __ksym;
+void bpf_kfunc_call_test_sleepable(void) __ksym;

void bpf_kfunc_call_test_offset(struct prog_test_ref_kfunc *p);
struct prog_test_member *bpf_kfunc_call_memb_acquire(void);
diff --git a/tools/testing/selftests/bpf/progs/wq.c b/tools/testing/selftests/bpf/progs/wq.c
index f92466eb8fb1..c0a094c84834 100644
--- a/tools/testing/selftests/bpf/progs/wq.c
+++ b/tools/testing/selftests/bpf/progs/wq.c
@@ -49,7 +49,9 @@ struct {
__type(value, struct elem);
} lru SEC(".maps");

-static int test_elem_callback(void *map, int *key)
+static int test_elem_callback(void *map, int *key,
+ int (callback_fn)(void *map, int *key, struct bpf_wq *wq),
+ u64 callback_flags)
{
struct elem init = {}, *val;
struct bpf_wq *wq;
@@ -63,13 +65,18 @@ static int test_elem_callback(void *map, int *key)
return -2;

wq = &val->w;
- if (bpf_wq_init(wq, map, 0) != 0)
+ if (bpf_wq_init(wq, map, callback_flags) != 0)
return -3;

+ if (bpf_wq_set_callback(wq, callback_fn, callback_flags))
+ return -4;
+
return 0;
}

-static int test_hmap_elem_callback(void *map, int *key)
+static int test_hmap_elem_callback(void *map, int *key,
+ int (callback_fn)(void *map, int *key, struct bpf_wq *wq),
+ u64 callback_flags)
{
struct hmap_elem init = {}, *val;
struct bpf_wq *wq;
@@ -85,6 +92,28 @@ static int test_hmap_elem_callback(void *map, int *key)
if (bpf_wq_init(wq, map, 0) != 0)
return -3;

+ if (bpf_wq_set_callback(wq, callback_fn, callback_flags))
+ return -4;
+
+ return 0;
+}
+
+__u32 ok;
+__u32 ok_sleepable;
+
+/* callback for non sleepable workqueue */
+static int wq_callback(void *map, int *key, struct bpf_wq *work)
+{
+ bpf_kfunc_common_test();
+ ok |= (1 << *key);
+ return 0;
+}
+
+/* callback for sleepable workqueue */
+static int wq_cb_sleepable(void *map, int *key, struct bpf_wq *work)
+{
+ bpf_kfunc_call_test_sleepable();
+ ok_sleepable |= (1 << *key);
return 0;
}

@@ -96,7 +125,8 @@ long test_call_array_sleepable(void *ctx)
{
int key = 0;

- return test_elem_callback(&array, &key);
+ return test_elem_callback(&array, &key, wq_cb_sleepable,
+ BPF_F_WQ_SLEEPABLE);
}

SEC("syscall")
@@ -107,7 +137,8 @@ long test_syscall_array_sleepable(void *ctx)
{
int key = 1;

- return test_elem_callback(&array, &key);
+ return test_elem_callback(&array, &key, wq_cb_sleepable,
+ BPF_F_WQ_SLEEPABLE);
}

SEC("tc")
@@ -118,7 +149,7 @@ long test_call_hash_sleepable(void *ctx)
{
int key = 2;

- return test_hmap_elem_callback(&hmap, &key);
+ return test_hmap_elem_callback(&hmap, &key, wq_callback, 0);
}

SEC("tc")
@@ -130,7 +161,7 @@ long test_call_hash_malloc_sleepable(void *ctx)
{
int key = 3;

- return test_hmap_elem_callback(&hmap_malloc, &key);
+ return test_hmap_elem_callback(&hmap_malloc, &key, wq_callback, 0);
}

SEC("tc")
@@ -141,5 +172,5 @@ long test_call_lru_sleepable(void *ctx)
{
int key = 4;

- return test_elem_callback(&lru, &key);
+ return test_elem_callback(&lru, &key, wq_callback, 0);
}
diff --git a/tools/testing/selftests/bpf/progs/wq_failures.c b/tools/testing/selftests/bpf/progs/wq_failures.c
index a08b6c93a195..efde14516358 100644
--- a/tools/testing/selftests/bpf/progs/wq_failures.c
+++ b/tools/testing/selftests/bpf/progs/wq_failures.c
@@ -27,6 +27,20 @@ struct {
__type(value, struct elem);
} lru SEC(".maps");

+/* callback for non sleepable workqueue */
+static int wq_callback(void *map, int *key, struct bpf_wq *work)
+{
+ bpf_kfunc_common_test();
+ return 0;
+}
+
+/* callback for sleepable workqueue */
+static int wq_cb_sleepable(void *map, int *key, struct bpf_wq *work)
+{
+ bpf_kfunc_call_test_sleepable();
+ return 0;
+}
+
SEC("tc")
/* test that bpf_wq_init takes a map as a second argument
*/
@@ -80,3 +94,104 @@ long test_wq_init_wrong_map(void *ctx)

return 0;
}
+
+SEC("?tc")
+__log_level(2)
+__failure
+/* check that bpf_wq_set_callback() can not be called with a
+ * sleepable callback without BPF_F_WQ_SLEEPABLE
+ */
+__msg("mark_precise: frame0: regs=r1 stack= before")
+__msg(": (85) call bpf_kfunc_call_test_sleepable#") /* anchor message */
+__msg("program must be sleepable to call sleepable kfunc bpf_kfunc_call_test_sleepable")
+long test_call_sleepable_callback_missing_flag(void *ctx)
+{
+ int key = 0;
+ struct bpf_wq *wq;
+
+ wq = bpf_map_lookup_elem(&array, &key);
+ if (wq) {
+ bpf_wq_init(wq, &array, 0);
+ bpf_wq_set_callback(wq, wq_cb_sleepable, 0);
+ }
+
+ return 0;
+}
+
+SEC("tc")
+/* check that calling a non sleepable callback with
+ * bpf_wq_set_callback() while providing BPF_F_WQ_SLEEPABLE
+ * fails.
+ */
+__retval(3)
+long test_call_non_sleepable_callback_wrong_flag(void *ctx)
+{
+ int key = 1;
+ struct bpf_wq *wq;
+
+ wq = bpf_map_lookup_elem(&array, &key);
+ if (!wq)
+ return 1;
+
+ if (bpf_wq_init(wq, &array, 0))
+ return 2;
+
+ if (bpf_wq_set_callback(wq, wq_callback, BPF_F_WQ_SLEEPABLE))
+ return 3;
+
+ return -22;
+}
+
+SEC("?tc")
+__log_level(2)
+__failure
+/* check that the first argument of bpf_wq_set_callback()
+ * is a correct bpf_wq pointer.
+ */
+__msg("mark_precise: frame0: regs=r1 stack= before")
+__msg(": (85) call bpf_wq_set_callback_impl#") /* anchor message */
+__msg("arg#0 doesn't point to a map value")
+long test_wrong_wq_pointer(void *ctx)
+{
+ int key = 0;
+ struct bpf_wq *wq;
+
+ wq = bpf_map_lookup_elem(&array, &key);
+ if (!wq)
+ return 1;
+
+ if (bpf_wq_init(wq, &array, 0))
+ return 2;
+
+ if (bpf_wq_set_callback((void *)&wq, wq_callback, 0))
+ return 3;
+
+ return -22;
+}
+
+SEC("?tc")
+__log_level(2)
+__failure
+/* check that the first argument of bpf_wq_set_callback()
+ * is a correct bpf_wq pointer.
+ */
+__msg("mark_precise: frame0: regs=r1 stack= before")
+__msg(": (85) call bpf_wq_set_callback_impl#") /* anchor message */
+__msg("off 1 doesn't point to 'struct bpf_wq' that is at 0")
+long test_wrong_wq_pointer_offset(void *ctx)
+{
+ int key = 0;
+ struct bpf_wq *wq;
+
+ wq = bpf_map_lookup_elem(&array, &key);
+ if (!wq)
+ return 1;
+
+ if (bpf_wq_init(wq, &array, 0))
+ return 2;
+
+ if (bpf_wq_set_callback((void *)wq + 1, wq_cb_sleepable, 0))
+ return 3;
+
+ return -22;
+}

--
2.44.0