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Commit c9d221f8 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
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fault-injection: add CPU notifier error injection module 



I used this module to test the series of modification to the cpu notifiers
code.

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

	# modprobe cpu-notifier-error-inject cpu_down_prepare_error=-1
	# echo 0 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: Operation not permitted

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

	# modprobe cpu-notifier-error-inject cpu_up_prepare_error=-2
	# echo 1 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: No such file or directory

[akpm@linux-foundation.org: fix Kconfig help text]
Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 55af6bb5

lib/Kconfig.debug

+12 −0
Original line number Diff line number Diff line
@@ -898,6 +898,18 @@ config LKDTM 
	Documentation on how to use the module can be found in

	Documentation/fault-injection/provoke-crashes.txt



config CPU_NOTIFIER_ERROR_INJECT

	tristate "CPU notifier error injection module"

	depends on HOTPLUG_CPU && DEBUG_KERNEL

	help

	  This option provides a kernel module that can be used to test

	  the error handling of the cpu notifiers



	  To compile this code as a module, choose M here: the module will

	  be called cpu-notifier-error-inject.



	  If unsure, say N.



config FAULT_INJECTION

	bool "Fault-injection framework"

	depends on DEBUG_KERNEL

lib/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ obj-$(CONFIG_AUDIT_GENERIC) += audit.o 
obj-$(CONFIG_SWIOTLB) += swiotlb.o

obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o

obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o

obj-$(CONFIG_CPU_NOTIFIER_ERROR_INJECT) += cpu-notifier-error-inject.o



lib-$(CONFIG_GENERIC_BUG) += bug.o

lib/cpu-notifier-error-inject.c

0 → 100644
+63 −0
Original line number Diff line number Diff line 
#include <linux/kernel.h>

#include <linux/cpu.h>

#include <linux/module.h>

#include <linux/notifier.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;

	}

	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 int err_inject_init(void)

{

	err_inject_cpu_notifier.priority = priority;



	return register_hotcpu_notifier(&err_inject_cpu_notifier);

}



static void err_inject_exit(void)

{

	unregister_hotcpu_notifier(&err_inject_cpu_notifier);

}



module_init(err_inject_init);

module_exit(err_inject_exit);



MODULE_DESCRIPTION("CPU notifier error injection module");

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");