8d43828814
This patchset provides kernel modules that can be used to test the error handling of notifier call chain failures by injecting artifical errors to the following notifier chain callbacks. * CPU notifier * PM notifier * memory hotplug notifier * powerpc pSeries reconfig notifier Example: 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 The patchset also adds cpu and memory hotplug tests to tools/testing/selftests These tests first do simple online and offline test and then do fault injection tests if notifier error injection module is available. This patch: The notifier error injection provides the ability to inject artifical errors to specified notifier chain callbacks. It is useful to test the error handling of notifier call chain failures. This adds common basic functions to define which type of events can be fail and to initialize the debugfs interface to control what error code should be returned and which event should be failed. 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>
112 lines
2.7 KiB
C
112 lines
2.7 KiB
C
#include <linux/module.h>
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#include "notifier-error-inject.h"
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static int debugfs_errno_set(void *data, u64 val)
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{
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*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
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return 0;
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}
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static int debugfs_errno_get(void *data, u64 *val)
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{
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*val = *(int *)data;
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return 0;
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}
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DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
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"%lld\n");
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static struct dentry *debugfs_create_errno(const char *name, mode_t mode,
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struct dentry *parent, int *value)
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{
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return debugfs_create_file(name, mode, parent, value, &fops_errno);
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}
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static int notifier_err_inject_callback(struct notifier_block *nb,
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unsigned long val, void *p)
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{
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int err = 0;
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struct notifier_err_inject *err_inject =
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container_of(nb, struct notifier_err_inject, nb);
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struct notifier_err_inject_action *action;
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for (action = err_inject->actions; action->name; action++) {
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if (action->val == val) {
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err = action->error;
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break;
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}
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}
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if (err)
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pr_info("Injecting error (%d) to %s\n", err, action->name);
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return notifier_from_errno(err);
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}
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struct dentry *notifier_err_inject_dir;
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EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
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struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
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struct notifier_err_inject *err_inject, int priority)
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{
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struct notifier_err_inject_action *action;
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mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
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struct dentry *dir;
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struct dentry *actions_dir;
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err_inject->nb.notifier_call = notifier_err_inject_callback;
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err_inject->nb.priority = priority;
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dir = debugfs_create_dir(name, parent);
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if (!dir)
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return ERR_PTR(-ENOMEM);
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actions_dir = debugfs_create_dir("actions", dir);
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if (!actions_dir)
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goto fail;
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for (action = err_inject->actions; action->name; action++) {
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struct dentry *action_dir;
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action_dir = debugfs_create_dir(action->name, actions_dir);
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if (!action_dir)
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goto fail;
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/*
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* Create debugfs r/w file containing action->error. If
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* notifier call chain is called with action->val, it will
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* fail with the error code
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*/
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if (!debugfs_create_errno("error", mode, action_dir,
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&action->error))
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goto fail;
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}
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return dir;
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fail:
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debugfs_remove_recursive(dir);
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return ERR_PTR(-ENOMEM);
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}
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EXPORT_SYMBOL_GPL(notifier_err_inject_init);
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static int __init err_inject_init(void)
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{
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notifier_err_inject_dir =
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debugfs_create_dir("notifier-error-inject", NULL);
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if (!notifier_err_inject_dir)
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return -ENOMEM;
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return 0;
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}
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static void __exit err_inject_exit(void)
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{
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debugfs_remove_recursive(notifier_err_inject_dir);
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}
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module_init(err_inject_init);
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module_exit(err_inject_exit);
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MODULE_DESCRIPTION("Notifier error injection module");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
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