1 files changed, 159 insertions, 5 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
index 035c263aab1b..a176bd75a748 100644
--- a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
+++ b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c
@@ -3,12 +3,16 @@
 
 #define _GNU_SOURCE         /* See feature_test_macros(7) */
 #include <unistd.h>
+#include <sched.h>
+#include <pthread.h>
 #include <sys/syscall.h>   /* For SYS_xxx definitions */
 #include <sys/types.h>
 #include <test_progs.h>
+#include "task_local_storage_helpers.h"
 #include "task_local_storage.skel.h"
 #include "task_local_storage_exit_creds.skel.h"
 #include "task_ls_recursion.skel.h"
+#include "task_storage_nodeadlock.skel.h"
 
 static void test_sys_enter_exit(void)
 {
@@ -39,7 +43,8 @@ out:
 static void test_exit_creds(void)
 {
 	struct task_local_storage_exit_creds *skel;
-	int err;
+	int err, run_count, sync_rcu_calls = 0;
+	const int MAX_SYNC_RCU_CALLS = 1000;
 
 	skel = task_local_storage_exit_creds__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
@@ -53,8 +58,19 @@ static void test_exit_creds(void)
 	if (CHECK_FAIL(system("ls > /dev/null")))
 		goto out;
 
-	/* sync rcu to make sure exit_creds() is called for "ls" */
-	kern_sync_rcu();
+	/* kern_sync_rcu is not enough on its own as the read section we want
+	 * to wait for may start after we enter synchronize_rcu, so our call
+	 * won't wait for the section to finish. Loop on the run counter
+	 * as well to ensure the program has run.
+	 */
+	do {
+		kern_sync_rcu();
+		run_count = __atomic_load_n(&skel->bss->run_count, __ATOMIC_SEQ_CST);
+	} while (run_count == 0 && ++sync_rcu_calls < MAX_SYNC_RCU_CALLS);
+
+	ASSERT_NEQ(sync_rcu_calls, MAX_SYNC_RCU_CALLS,
+		   "sync_rcu count too high");
+	ASSERT_NEQ(run_count, 0, "run_count");
 	ASSERT_EQ(skel->bss->valid_ptr_count, 0, "valid_ptr_count");
 	ASSERT_NEQ(skel->bss->null_ptr_count, 0, "null_ptr_count");
 out:
@@ -63,24 +79,160 @@ out:
 
 static void test_recursion(void)
 {
+	int err, map_fd, prog_fd, task_fd;
 	struct task_ls_recursion *skel;
-	int err;
+	struct bpf_prog_info info;
+	__u32 info_len = sizeof(info);
+	long value;
+
+	task_fd = sys_pidfd_open(getpid(), 0);
+	if (!ASSERT_NEQ(task_fd, -1, "sys_pidfd_open"))
+		return;
 
 	skel = task_ls_recursion__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
-		return;
+		goto out;
 
 	err = task_ls_recursion__attach(skel);
 	if (!ASSERT_OK(err, "skel_attach"))
 		goto out;
 
 	/* trigger sys_enter, make sure it does not cause deadlock */
+	skel->bss->test_pid = getpid();
 	syscall(SYS_gettid);
+	skel->bss->test_pid = 0;
+	task_ls_recursion__detach(skel);
+
+	/* Refer to the comment in BPF_PROG(on_update) for
+	 * the explanation on the value 201 and 100.
+	 */
+	map_fd = bpf_map__fd(skel->maps.map_a);
+	err = bpf_map_lookup_elem(map_fd, &task_fd, &value);
+	ASSERT_OK(err, "lookup map_a");
+	ASSERT_EQ(value, 201, "map_a value");
+	ASSERT_EQ(skel->bss->nr_del_errs, 1, "bpf_task_storage_delete busy");
+
+	map_fd = bpf_map__fd(skel->maps.map_b);
+	err = bpf_map_lookup_elem(map_fd, &task_fd, &value);
+	ASSERT_OK(err, "lookup map_b");
+	ASSERT_EQ(value, 100, "map_b value");
+
+	prog_fd = bpf_program__fd(skel->progs.on_lookup);
+	memset(&info, 0, sizeof(info));
+	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
+	ASSERT_OK(err, "get prog info");
+	ASSERT_GT(info.recursion_misses, 0, "on_lookup prog recursion");
+
+	prog_fd = bpf_program__fd(skel->progs.on_update);
+	memset(&info, 0, sizeof(info));
+	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
+	ASSERT_OK(err, "get prog info");
+	ASSERT_EQ(info.recursion_misses, 0, "on_update prog recursion");
+
+	prog_fd = bpf_program__fd(skel->progs.on_enter);
+	memset(&info, 0, sizeof(info));
+	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
+	ASSERT_OK(err, "get prog info");
+	ASSERT_EQ(info.recursion_misses, 0, "on_enter prog recursion");
 
 out:
+	close(task_fd);
 	task_ls_recursion__destroy(skel);
 }
 
+static bool stop;
+
+static void waitall(const pthread_t *tids, int nr)
+{
+	int i;
+
+	stop = true;
+	for (i = 0; i < nr; i++)
+		pthread_join(tids[i], NULL);
+}
+
+static void *sock_create_loop(void *arg)
+{
+	struct task_storage_nodeadlock *skel = arg;
+	int fd;
+
+	while (!stop) {
+		fd = socket(AF_INET, SOCK_STREAM, 0);
+		close(fd);
+		if (skel->bss->nr_get_errs || skel->bss->nr_del_errs)
+			stop = true;
+	}
+
+	return NULL;
+}
+
+static void test_nodeadlock(void)
+{
+	struct task_storage_nodeadlock *skel;
+	struct bpf_prog_info info = {};
+	__u32 info_len = sizeof(info);
+	const int nr_threads = 32;
+	pthread_t tids[nr_threads];
+	int i, prog_fd, err;
+	cpu_set_t old, new;
+
+	/* Pin all threads to one cpu to increase the chance of preemption
+	 * in a sleepable bpf prog.
+	 */
+	CPU_ZERO(&new);
+	CPU_SET(0, &new);
+	err = sched_getaffinity(getpid(), sizeof(old), &old);
+	if (!ASSERT_OK(err, "getaffinity"))
+		return;
+	err = sched_setaffinity(getpid(), sizeof(new), &new);
+	if (!ASSERT_OK(err, "setaffinity"))
+		return;
+
+	skel = task_storage_nodeadlock__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "open_and_load"))
+		goto done;
+
+	/* Unnecessary recursion and deadlock detection are reproducible
+	 * in the preemptible kernel.
+	 */
+	if (!skel->kconfig->CONFIG_PREEMPT) {
+		test__skip();
+		goto done;
+	}
+
+	err = task_storage_nodeadlock__attach(skel);
+	ASSERT_OK(err, "attach prog");
+
+	for (i = 0; i < nr_threads; i++) {
+		err = pthread_create(&tids[i], NULL, sock_create_loop, skel);
+		if (err) {
+			/* Only assert once here to avoid excessive
+			 * PASS printing during test failure.
+			 */
+			ASSERT_OK(err, "pthread_create");
+			waitall(tids, i);
+			goto done;
+		}
+	}
+
+	/* With 32 threads, 1s is enough to reproduce the issue */
+	sleep(1);
+	waitall(tids, nr_threads);
+
+	info_len = sizeof(info);
+	prog_fd = bpf_program__fd(skel->progs.socket_post_create);
+	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
+	ASSERT_OK(err, "get prog info");
+	ASSERT_EQ(info.recursion_misses, 0, "prog recursion");
+
+	ASSERT_EQ(skel->bss->nr_get_errs, 0, "bpf_task_storage_get busy");
+	ASSERT_EQ(skel->bss->nr_del_errs, 0, "bpf_task_storage_delete busy");
+
+done:
+	task_storage_nodeadlock__destroy(skel);
+	sched_setaffinity(getpid(), sizeof(old), &old);
+}
+
 void test_task_local_storage(void)
 {
 	if (test__start_subtest("sys_enter_exit"))
@@ -89,4 +241,6 @@ void test_task_local_storage(void)
 		test_exit_creds();
 	if (test__start_subtest("recursion"))
 		test_recursion();
+	if (test__start_subtest("nodeadlock"))
+		test_nodeadlock();
 }