memory: memory notifier error injection module
This provides the ability to inject artifical errors to memory hotplug
notifier chain callbacks. It is controlled through debugfs interface
under /sys/kernel/debug/notifier-error-inject/memory
If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".
Example: Inject memory hotplug offline error (-12 == -ENOMEM)
# cd /sys/kernel/debug/notifier-error-inject/memory
# echo -12 > actions/MEM_GOING_OFFLINE/error
# echo offline > /sys/devices/system/memory/memoryXXX/state
bash: echo: write error: Cannot allocate memory
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>
diff --git a/lib/memory-notifier-error-inject.c b/lib/memory-notifier-error-inject.c
new file mode 100644
index 0000000..e6239bf
--- /dev/null
+++ b/lib/memory-notifier-error-inject.c
@@ -0,0 +1,48 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/memory.h>
+
+#include "notifier-error-inject.h"
+
+static int priority;
+module_param(priority, int, 0);
+MODULE_PARM_DESC(priority, "specify memory notifier priority");
+
+static struct notifier_err_inject memory_notifier_err_inject = {
+ .actions = {
+ { NOTIFIER_ERR_INJECT_ACTION(MEM_GOING_ONLINE) },
+ { NOTIFIER_ERR_INJECT_ACTION(MEM_GOING_OFFLINE) },
+ {}
+ }
+};
+
+static struct dentry *dir;
+
+static int err_inject_init(void)
+{
+ int err;
+
+ dir = notifier_err_inject_init("memory", notifier_err_inject_dir,
+ &memory_notifier_err_inject, priority);
+ if (IS_ERR(dir))
+ return PTR_ERR(dir);
+
+ err = register_memory_notifier(&memory_notifier_err_inject.nb);
+ if (err)
+ debugfs_remove_recursive(dir);
+
+ return err;
+}
+
+static void err_inject_exit(void)
+{
+ unregister_memory_notifier(&memory_notifier_err_inject.nb);
+ debugfs_remove_recursive(dir);
+}
+
+module_init(err_inject_init);
+module_exit(err_inject_exit);
+
+MODULE_DESCRIPTION("memory notifier error injection module");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");