[bpf-next,v2,12/16] selftests/bpf: wq: add bpf_wq_init() checks

diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 3329ea080865..785b91b629be 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -470,4 +470,5 @@  extern int bpf_iter_css_new(struct bpf_iter_css *it,
 extern struct cgroup_subsys_state *bpf_iter_css_next(struct bpf_iter_css *it) __weak __ksym;
 extern void bpf_iter_css_destroy(struct bpf_iter_css *it) __weak __ksym;
 
+extern int bpf_wq_init(struct bpf_wq *wq, void *p__map, unsigned int flags) __weak __ksym;
 #endif
diff --git a/tools/testing/selftests/bpf/prog_tests/wq.c b/tools/testing/selftests/bpf/prog_tests/wq.c
index 9a07b8bc2c52..26ab69796103 100644
--- a/tools/testing/selftests/bpf/prog_tests/wq.c
+++ b/tools/testing/selftests/bpf/prog_tests/wq.c
@@ -2,6 +2,7 @@ 
 /* Copyright (c) 2024 Benjamin Tissoires */
 #include <test_progs.h>
 #include "wq.skel.h"
+#include "wq_failures.skel.h"
 
 void serial_test_wq(void)
 {
@@ -9,3 +10,10 @@  void serial_test_wq(void)
 
 	RUN_TESTS(wq);
 }
+
+void serial_test_failures_wq(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+
+	RUN_TESTS(wq_failures);
+}
diff --git a/tools/testing/selftests/bpf/progs/wq.c b/tools/testing/selftests/bpf/progs/wq.c
index 8c668ad04059..f92466eb8fb1 100644
--- a/tools/testing/selftests/bpf/progs/wq.c
+++ b/tools/testing/selftests/bpf/progs/wq.c
@@ -52,6 +52,7 @@  struct {
 static int test_elem_callback(void *map, int *key)
 {
 	struct elem init = {}, *val;
+	struct bpf_wq *wq;
 
 	if (map == &lru &&
 	    bpf_map_update_elem(map, key, &init, 0))
@@ -61,12 +62,17 @@  static int test_elem_callback(void *map, int *key)
 	if (!val)
 		return -2;
 
+	wq = &val->w;
+	if (bpf_wq_init(wq, map, 0) != 0)
+		return -3;
+
 	return 0;
 }
 
 static int test_hmap_elem_callback(void *map, int *key)
 {
 	struct hmap_elem init = {}, *val;
+	struct bpf_wq *wq;
 
 	if (bpf_map_update_elem(map, key, &init, 0))
 		return -1;
@@ -75,6 +81,10 @@  static int test_hmap_elem_callback(void *map, int *key)
 	if (!val)
 		return -2;
 
+	wq = &val->work;
+	if (bpf_wq_init(wq, map, 0) != 0)
+		return -3;
+
 	return 0;
 }
 
diff --git a/tools/testing/selftests/bpf/progs/wq_failures.c b/tools/testing/selftests/bpf/progs/wq_failures.c
new file mode 100644
index 000000000000..db7015c7d541
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/wq_failures.c
@@ -0,0 +1,78 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Benjamin Tissoires
+ */
+
+#include "bpf_experimental.h"
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
+
+char _license[] SEC("license") = "GPL";
+
+struct elem {
+	struct bpf_wq w;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 2);
+	__type(key, int);
+	__type(value, struct elem);
+} array SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_LRU_HASH);
+	__uint(max_entries, 4);
+	__type(key, int);
+	__type(value, struct elem);
+} lru SEC(".maps");
+
+SEC("tc")
+/* test that bpf_wq_init takes a map as a second argument
+ */
+__log_level(2)
+__flag(BPF_F_TEST_STATE_FREQ)
+__failure
+__msg(": (85) call bpf_wq_init#") /* anchor message */
+__msg("pointer in R2 isn't map pointer")
+long test_wq_init_nomap(void *ctx)
+{
+	struct bpf_wq *wq;
+	struct elem *val;
+	int key = 0;
+
+	val = bpf_map_lookup_elem(&array, &key);
+	if (!val)
+		return -1;
+
+	wq = &val->w;
+	if (bpf_wq_init(wq, &key, 0) != 0)
+		return -3;
+
+	return 0;
+}
+
+SEC("tc")
+/* test that the workqueue is part of the map in bpf_wq_init
+ */
+__log_level(2)
+__flag(BPF_F_TEST_STATE_FREQ)
+__failure
+__msg(": (85) call bpf_wq_init#") /* anchor message */
+__msg("workqueue pointer in R1 map_uid=0 doesn't match map pointer in R2 map_uid=0")
+long test_wq_init_wrong_map(void *ctx)
+{
+	struct bpf_wq *wq;
+	struct elem *val;
+	int key = 0;
+
+	val = bpf_map_lookup_elem(&array, &key);
+	if (!val)
+		return -1;
+
+	wq = &val->w;
+	if (bpf_wq_init(wq, &lru, 0) != 0)
+		return -3;
+
+	return 0;
+}