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Commit 19ec673c authored by Cyrill Gorcunov's avatar Cyrill Gorcunov Committed by Ingo Molnar
Browse files

x86: nmi - fix incorrect NMI watchdog used by default 



The commit

	commit 4b82b277
	Author: Cyrill Gorcunov <gorcunov@gmail.com>
	Date:   Sat May 24 19:36:35 2008 +0400

set nmi_watchdog to NMI_IO_APIC as by default. This causes hangs on some
machines with buggy watchdogs. Fix it - i.e. restore old behaviour.

Thanks to Sitsofe Wheeler and Adrian Bunk for catching the problem
and Maciej W. Rozycki for explanation what is going on there.

Signed-off-by: default avatarCyrill Gorcunov <gorcunov@gmail.com>
CC: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1798bc22

arch/x86/kernel/nmi.c

+9 −7
Original line number Diff line number Diff line
@@ -84,20 +84,15 @@ static inline unsigned int get_timer_irqs(int cpu) 
#endif

}



#ifdef CONFIG_X86_64

/* Run after command line and cpu_init init, but before all other checks */

void nmi_watchdog_default(void)

{

	if (nmi_watchdog != NMI_DEFAULT)

		return;

#ifdef CONFIG_X86_64

	nmi_watchdog = NMI_NONE;

#else

	if (lapic_watchdog_ok())

		nmi_watchdog = NMI_LOCAL_APIC;

	else

		nmi_watchdog = NMI_IO_APIC;

#endif

}

#endif



#ifdef CONFIG_SMP

/*
@@ -488,8 +483,15 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file, 
		return -EIO;

	}



#ifdef CONFIG_X86_64

	/* if nmi_watchdog is not set yet, then set it */

	nmi_watchdog_default();

#else

	if (lapic_watchdog_ok())

		nmi_watchdog = NMI_LOCAL_APIC;

	else

		nmi_watchdog = NMI_IO_APIC;

#endif



	if (nmi_watchdog == NMI_LOCAL_APIC) {

		if (nmi_watchdog_enabled)

include/asm-x86/nmi.h

+3 −1
Original line number Diff line number Diff line
@@ -38,9 +38,11 @@ static inline void unset_nmi_pm_callback(struct pm_dev *dev) 


#ifdef CONFIG_X86_64

extern void default_do_nmi(struct pt_regs *);

extern void nmi_watchdog_default(void);

#else

#define nmi_watchdog_default(void) do {} while (0)

#endif



extern void nmi_watchdog_default(void);

extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);

extern int check_nmi_watchdog(void);

extern int nmi_watchdog_enabled;