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Revision a0cff57bb2a41cb9cbf13d3203097b4156d8c0ae authored by Davidlohr Bueso on 13 September 2017, 20:08:21 UTC, committed by Paolo Bonzini on 15 September 2017, 14:57:12 UTC 
kvm,x86: Fix apf_task_wake_one() wq serialization
 
During code inspection, the following potential race was seen:

CPU0   	    		    	     	CPU1
kvm_async_pf_task_wait			apf_task_wake_one
					  [L] swait_active(&n->wq)
  [S] prepare_to_swait(&n.wq)
  [L] if (!hlist_unhahed(&n.link))
	schedule()			  [S] hlist_del_init(&n->link);

Properly serialize swait_active() checks such that a wakeup is
not missed.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent cc1b468
Raw File
rtc-efi-platform.c 
/*
 * Moved from arch/ia64/kernel/time.c
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *	Stephane Eranian <eranian@hpl.hp.com>
 *	David Mosberger <davidm@hpl.hp.com>
 * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
 * Copyright (C) 1999-2000 VA Linux Systems
 * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/efi.h>
#include <linux/platform_device.h>

static struct platform_device rtc_efi_dev = {
	.name = "rtc-efi",
	.id = -1,
};

static int __init rtc_init(void)
{
	if (efi_enabled(EFI_RUNTIME_SERVICES))
		if (platform_device_register(&rtc_efi_dev) < 0)
			pr_err("unable to register rtc device...\n");

	/* not necessarily an error */
	return 0;
}
module_init(rtc_init);
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