selftests/bpf: Add stress test for timer async cancel

Extend BPF timer selftest to run stress test for async cancel.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260201025403.66625-6-alexei.starovoitov@gmail.com

Author: mykyta5

tools/testing/selftests/bpf/prog_tests/timer.c

@@ -23,13 +23,14 @@ static void *spin_lock_thread(void *arg)
 }
 
 
-static int timer_stress(struct timer *timer_skel)
+static int timer_stress_runner(struct timer *timer_skel, bool async_cancel)
 {
 	int i, err = 1, prog_fd;
 	LIBBPF_OPTS(bpf_test_run_opts, topts);
 	pthread_t thread_id[NUM_THR];
 	void *ret;
 
+	timer_skel->bss->async_cancel = async_cancel;
 	prog_fd = bpf_program__fd(timer_skel->progs.race);
 	for (i = 0; i < NUM_THR; i++) {
 		err = pthread_create(&thread_id[i], NULL,
@@ -46,6 +47,16 @@ static int timer_stress(struct timer *timer_skel)
 	return err;
 }
 
+static int timer_stress(struct timer *timer_skel)
+{
+	return timer_stress_runner(timer_skel, false);
+}
+
+static int timer_stress_async_cancel(struct timer *timer_skel)
+{
+	return timer_stress_runner(timer_skel, true);
+}
+
 static int timer(struct timer *timer_skel)
 {
 	int err, prog_fd;
@@ -118,6 +129,11 @@ void serial_test_timer_stress(void)
 	test_timer(timer_stress);
 }
 
+void serial_test_timer_stress_async_cancel(void)
+{
+	test_timer(timer_stress_async_cancel);
+}
+
 void test_timer_interrupt(void)
 {
 	struct timer_interrupt *skel = NULL;

tools/testing/selftests/bpf/progs/timer.c

@@ -1,13 +1,17 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2021 Facebook */
-#include <linux/bpf.h>
-#include <time.h>
+
+#include <vmlinux.h>
 #include <stdbool.h>
 #include <errno.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 
+#define CLOCK_MONOTONIC 1
+#define CLOCK_BOOTTIME 7
+
 char _license[] SEC("license") = "GPL";
+
 struct hmap_elem {
 	int counter;
 	struct bpf_timer timer;
@@ -63,6 +67,7 @@ __u64 callback_check = 52;
 __u64 callback2_check = 52;
 __u64 pinned_callback_check;
 __s32 pinned_cpu;
+bool async_cancel = 0;
 
 #define ARRAY 1
 #define HTAB 2
@@ -419,7 +424,10 @@ int race(void *ctx)
 
 	bpf_timer_set_callback(timer, race_timer_callback);
 	bpf_timer_start(timer, 0, 0);
-	bpf_timer_cancel(timer);
+	if (async_cancel)
+		bpf_timer_cancel_async(timer);
+	else
+		bpf_timer_cancel(timer);
 
 	return 0;
 }