cpu: rewrite cpu-notifier-error-inject module

Rewrite existing cpu-notifier-error-inject module to use debugfs based new
framework.

This change removes cpu_up_prepare_error and cpu_down_prepare_error module
parameters which were used to specify error code to be injected.  We could
keep these module parameters for backward compatibility by module_param_cb
but it seems overkill for this module.

This provides the ability to inject artifical errors to CPU notifier chain
callbacks.  It is controlled through debugfs interface under
/sys/kernel/debug/notifier-error-inject/cpu

If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".

Example1: inject CPU offline error (-1 == -EPERM)

	# cd /sys/kernel/debug/notifier-error-inject/cpu
	# echo -1 > actions/CPU_DOWN_PREPARE/error
	# echo 0 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: Operation not permitted

Example2: inject CPU online error (-2 == -ENOENT)

	# cd /sys/kernel/debug/notifier-error-inject/cpu
	# echo -2 > actions/CPU_UP_PREPARE/error
	# echo 1 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: No such file or directory

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Akinobu Mita 2012-07-30 14:43:03 -07:00 committed by Linus Torvalds
parent 8d43828814
commit f5a9f52e2c
2 changed files with 39 additions and 40 deletions

View file

@ -1,58 +1,45 @@
#include <linux/kernel.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include "notifier-error-inject.h"
static int priority;
static int cpu_up_prepare_error;
static int cpu_down_prepare_error;
module_param(priority, int, 0);
MODULE_PARM_DESC(priority, "specify cpu notifier priority");
module_param(cpu_up_prepare_error, int, 0644);
MODULE_PARM_DESC(cpu_up_prepare_error,
"specify error code to inject CPU_UP_PREPARE action");
module_param(cpu_down_prepare_error, int, 0644);
MODULE_PARM_DESC(cpu_down_prepare_error,
"specify error code to inject CPU_DOWN_PREPARE action");
static int err_inject_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
int err = 0;
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
err = cpu_up_prepare_error;
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
err = cpu_down_prepare_error;
break;
static struct notifier_err_inject cpu_notifier_err_inject = {
.actions = {
{ NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE) },
{ NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE_FROZEN) },
{ NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE) },
{ NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE_FROZEN) },
{}
}
if (err)
printk(KERN_INFO "Injecting error (%d) at cpu notifier\n", err);
return notifier_from_errno(err);
}
static struct notifier_block err_inject_cpu_notifier = {
.notifier_call = err_inject_cpu_callback,
};
static struct dentry *dir;
static int err_inject_init(void)
{
err_inject_cpu_notifier.priority = priority;
int err;
return register_hotcpu_notifier(&err_inject_cpu_notifier);
dir = notifier_err_inject_init("cpu", notifier_err_inject_dir,
&cpu_notifier_err_inject, priority);
if (IS_ERR(dir))
return PTR_ERR(dir);
err = register_hotcpu_notifier(&cpu_notifier_err_inject.nb);
if (err)
debugfs_remove_recursive(dir);
return err;
}
static void err_inject_exit(void)
{
unregister_hotcpu_notifier(&err_inject_cpu_notifier);
unregister_hotcpu_notifier(&cpu_notifier_err_inject.nb);
debugfs_remove_recursive(dir);
}
module_init(err_inject_init);