71 lines
1.7 KiB
C
71 lines
1.7 KiB
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
|
// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
|
||
|
|
|
||
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
||
|
|
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/workqueue.h>
|
||
|
|
#include <linux/delay.h>
|
||
|
|
|
||
|
|
/* load/run-time control from sysfs writer */
|
||
|
|
static bool block_transition;
|
||
|
|
module_param(block_transition, bool, 0644);
|
||
|
|
MODULE_PARM_DESC(block_transition, "block_transition (default=false)");
|
||
|
|
|
||
|
|
static void busymod_work_func(struct work_struct *work);
|
||
|
|
static DECLARE_WORK(work, busymod_work_func);
|
||
|
|
static DECLARE_COMPLETION(busymod_work_started);
|
||
|
|
|
||
|
|
static void busymod_work_func(struct work_struct *work)
|
||
|
|
{
|
||
|
|
pr_info("%s enter\n", __func__);
|
||
|
|
complete(&busymod_work_started);
|
||
|
|
|
||
|
|
while (READ_ONCE(block_transition)) {
|
||
|
|
/*
|
||
|
|
* Busy-wait until the sysfs writer has acknowledged a
|
||
|
|
* blocked transition and clears the flag.
|
||
|
|
*/
|
||
|
|
msleep(20);
|
||
|
|
}
|
||
|
|
|
||
|
|
pr_info("%s exit\n", __func__);
|
||
|
|
}
|
||
|
|
|
||
|
|
static int test_klp_callbacks_busy_init(void)
|
||
|
|
{
|
||
|
|
pr_info("%s\n", __func__);
|
||
|
|
schedule_work(&work);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* To synchronize kernel messages, hold the init function from
|
||
|
|
* exiting until the work function's entry message has printed.
|
||
|
|
*/
|
||
|
|
wait_for_completion(&busymod_work_started);
|
||
|
|
|
||
|
|
if (!block_transition) {
|
||
|
|
/*
|
||
|
|
* Serialize output: print all messages from the work
|
||
|
|
* function before returning from init().
|
||
|
|
*/
|
||
|
|
flush_work(&work);
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void test_klp_callbacks_busy_exit(void)
|
||
|
|
{
|
||
|
|
WRITE_ONCE(block_transition, false);
|
||
|
|
flush_work(&work);
|
||
|
|
pr_info("%s\n", __func__);
|
||
|
|
}
|
||
|
|
|
||
|
|
module_init(test_klp_callbacks_busy_init);
|
||
|
|
module_exit(test_klp_callbacks_busy_exit);
|
||
|
|
MODULE_LICENSE("GPL");
|
||
|
|
MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
|
||
|
|
MODULE_DESCRIPTION("Livepatch test: busy target module");
|