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

Commit Message

Benjamin Tissoires April 16, 2024, 2:08 p.m. UTC

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 <[e-mail]>
---
 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(-)

Comments

Song Liu April 18, 2024, 3:25 a.m. UTC | #1

On Tue, Apr 16, 2024 at 7:11 AM Benjamin Tissoires <[e-mail]> wrote:
[...]

> +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")

This line and some other "mark_precise" lines are causing issues for
test_progs-no_alu32 in the CI. I can reproduce it in my local tests.

I am not quite sure what is the best fix. Maybe we can just
remove it.

Thanks,
Song

> +__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
>

Benjamin Tissoires April 18, 2024, 8:55 a.m. UTC | #2

On Thu, Apr 18, 2024 at 5:25 AM Song Liu <[e-mail]> wrote:
>
> On Tue, Apr 16, 2024 at 7:11 AM Benjamin Tissoires <[e-mail]> wrote:
> [...]
>
> > +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")
>
> This line and some other "mark_precise" lines are causing issues for
> test_progs-no_alu32 in the CI. I can reproduce it in my local tests.
>

Indeed. I can also reproduce locally. Here, it only happens for
test_wq_init_nomap() and test_wq_init_wrong_map().
TBH, I'm not sure what "precise" means, I just copied the checks from
timer_failures.c.

>
> I am not quite sure what is the best fix. Maybe we can just
> remove it.

Given that most of the code is shared with timer, but given that we
are working with kfuncs, we are not using the same r0 registers.
So yeah, I would think we could rely on the timer tests for precise,
and drop them here...

Cheers,
Benjamin

>
>
> Thanks,
> Song
>
> > +__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
> >
>

Patch

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;
+}