diff options
Diffstat (limited to 'samples/hung_task/hung_task_mutex.c')
-rw-r--r-- | samples/hung_task/hung_task_mutex.c | 66 |
1 files changed, 0 insertions, 66 deletions
diff --git a/samples/hung_task/hung_task_mutex.c b/samples/hung_task/hung_task_mutex.c deleted file mode 100644 index 47ed38239ea3..000000000000 --- a/samples/hung_task/hung_task_mutex.c +++ /dev/null @@ -1,66 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * hung_task_mutex.c - Sample code which causes hung task by mutex - * - * Usage: load this module and read `<debugfs>/hung_task/mutex` - * by 2 or more processes. - * - * This is for testing kernel hung_task error message. - * Note that this will make your system freeze and maybe - * cause panic. So do not use this except for the test. - */ - -#include <linux/debugfs.h> -#include <linux/delay.h> -#include <linux/fs.h> -#include <linux/module.h> -#include <linux/mutex.h> - -#define HUNG_TASK_DIR "hung_task" -#define HUNG_TASK_FILE "mutex" -#define SLEEP_SECOND 256 - -static const char dummy_string[] = "This is a dummy string."; -static DEFINE_MUTEX(dummy_mutex); -static struct dentry *hung_task_dir; - -static ssize_t read_dummy(struct file *file, char __user *user_buf, - size_t count, loff_t *ppos) -{ - /* If the second task waits on the lock, it is uninterruptible sleep. */ - guard(mutex)(&dummy_mutex); - - /* When the first task sleep here, it is interruptible. */ - msleep_interruptible(SLEEP_SECOND * 1000); - - return simple_read_from_buffer(user_buf, count, ppos, - dummy_string, sizeof(dummy_string)); -} - -static const struct file_operations hung_task_fops = { - .read = read_dummy, -}; - -static int __init hung_task_sample_init(void) -{ - hung_task_dir = debugfs_create_dir(HUNG_TASK_DIR, NULL); - if (IS_ERR(hung_task_dir)) - return PTR_ERR(hung_task_dir); - - debugfs_create_file(HUNG_TASK_FILE, 0400, hung_task_dir, - NULL, &hung_task_fops); - - return 0; -} - -static void __exit hung_task_sample_exit(void) -{ - debugfs_remove_recursive(hung_task_dir); -} - -module_init(hung_task_sample_init); -module_exit(hung_task_sample_exit); - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Masami Hiramatsu"); -MODULE_DESCRIPTION("Simple sleep under mutex file for testing hung task"); |