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Revision 871341023c771ad233620b7a1fb3d9c7031c4e5c authored by Johannes Weiner on 12 September 2013, 22:13:38 UTC, committed by Linus Torvalds on 12 September 2013, 22:38:01 UTC 
arch: mm: do not invoke OOM killer on kernel fault OOM
 
Kernel faults are expected to handle OOM conditions gracefully (gup,
uaccess etc.), so they should never invoke the OOM killer.  Reserve this
for faults triggered in user context when it is the only option.

Most architectures already do this, fix up the remaining few.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: azurIt <azurit@pobox.sk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 94bce45
Raw File
notifier-error-inject.c 
#include <linux/module.h>

#include "notifier-error-inject.h"

static int debugfs_errno_set(void *data, u64 val)
{
	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
	return 0;
}

static int debugfs_errno_get(void *data, u64 *val)
{
	*val = *(int *)data;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
			"%lld\n");

static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
				struct dentry *parent, int *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_errno);
}

static int notifier_err_inject_callback(struct notifier_block *nb,
				unsigned long val, void *p)
{
	int err = 0;
	struct notifier_err_inject *err_inject =
		container_of(nb, struct notifier_err_inject, nb);
	struct notifier_err_inject_action *action;

	for (action = err_inject->actions; action->name; action++) {
		if (action->val == val) {
			err = action->error;
			break;
		}
	}
	if (err)
		pr_info("Injecting error (%d) to %s\n", err, action->name);

	return notifier_from_errno(err);
}

struct dentry *notifier_err_inject_dir;
EXPORT_SYMBOL_GPL(notifier_err_inject_dir);

struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
			struct notifier_err_inject *err_inject, int priority)
{
	struct notifier_err_inject_action *action;
	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
	struct dentry *dir;
	struct dentry *actions_dir;

	err_inject->nb.notifier_call = notifier_err_inject_callback;
	err_inject->nb.priority = priority;

	dir = debugfs_create_dir(name, parent);
	if (!dir)
		return ERR_PTR(-ENOMEM);

	actions_dir = debugfs_create_dir("actions", dir);
	if (!actions_dir)
		goto fail;

	for (action = err_inject->actions; action->name; action++) {
		struct dentry *action_dir;

		action_dir = debugfs_create_dir(action->name, actions_dir);
		if (!action_dir)
			goto fail;

		/*
		 * Create debugfs r/w file containing action->error. If
		 * notifier call chain is called with action->val, it will
		 * fail with the error code
		 */
		if (!debugfs_create_errno("error", mode, action_dir,
					&action->error))
			goto fail;
	}
	return dir;
fail:
	debugfs_remove_recursive(dir);
	return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL_GPL(notifier_err_inject_init);

static int __init err_inject_init(void)
{
	notifier_err_inject_dir =
		debugfs_create_dir("notifier-error-inject", NULL);

	if (!notifier_err_inject_dir)
		return -ENOMEM;

	return 0;
}

static void __exit err_inject_exit(void)
{
	debugfs_remove_recursive(notifier_err_inject_dir);
}

module_init(err_inject_init);
module_exit(err_inject_exit);

MODULE_DESCRIPTION("Notifier error injection module");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
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