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Revision 4cdd2ad78098244c1bc9ec4374ea1c225fd1cd6f authored by Mike Snitzer on 13 May 2014, 17:49:39 UTC, committed by Mike Snitzer on 14 May 2014, 20:12:17 UTC 
dm mpath: fix lock order inconsistency in multipath_ioctl
 
Commit 3e9f1be1b40 ("dm mpath: remove process_queued_ios()") did not
consistently take the multipath device's spinlock (m->lock) before
calling dm_table_run_md_queue_async() -- which takes the q->queue_lock.

Found with code inspection using hint from reported lockdep warning.

Reported-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1 parent 85ad643
Raw File
cpu-notifier-error-inject.c 
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/cpu.h>

#include "notifier-error-inject.h"

static int priority;
module_param(priority, int, 0);
MODULE_PARM_DESC(priority, "specify cpu notifier priority");

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) },
		{}
	}
};

static struct dentry *dir;

static int err_inject_init(void)
{
	int err;

	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(&cpu_notifier_err_inject.nb);
	debugfs_remove_recursive(dir);
}

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>");
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