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Commit 553f265f authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[PATCH] x86_64: Don't run NMI watchdog during machine checks 



Machine checks can stall the machine for a long time and
it's not good to trigger the nmi watchdog during that.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent be56db61

arch/x86_64/kernel/mce.c

+7 −1
Original line number Diff line number Diff line
@@ -29,6 +29,8 @@ 
#define MISC_MCELOG_MINOR 227

#define NR_BANKS 6



atomic_t mce_entry;



static int mce_dont_init;



/* 0: always panic, 1: panic if deadlock possible, 2: try to avoid panic,
@@ -172,10 +174,12 @@ void do_machine_check(struct pt_regs * regs, long error_code) 
	int i;

	int panicm_found = 0;



	atomic_inc(&mce_entry);



	if (regs)

		notify_die(DIE_NMI, "machine check", regs, error_code, 18, SIGKILL);

	if (!banks)

		return;

		goto out2;



	memset(&m, 0, sizeof(struct mce));

	m.cpu = safe_smp_processor_id();
@@ -266,6 +270,8 @@ void do_machine_check(struct pt_regs * regs, long error_code) 
 out:

	/* Last thing done in the machine check exception to clear state. */

	wrmsrl(MSR_IA32_MCG_STATUS, 0);

 out2:

	atomic_dec(&mce_entry);

}



/*

arch/x86_64/kernel/nmi.c

+7 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <asm/proto.h>

#include <asm/kdebug.h>

#include <asm/local.h>

#include <asm/mce.h>



/*

 * lapic_nmi_owner tracks the ownership of the lapic NMI hardware:
@@ -480,6 +481,12 @@ void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) 
		__get_cpu_var(nmi_touch) = 0;

		touched = 1;

	}

#ifdef CONFIG_X86_MCE

	/* Could check oops_in_progress here too, but it's safer

	   not too */

	if (atomic_read(&mce_entry) > 0)

		touched = 1;

#endif

	if (!touched && __get_cpu_var(last_irq_sum) == sum) {

		/*

		 * Ayiee, looks like this CPU is stuck ...

include/asm-x86_64/mce.h

+7 −0
Original line number Diff line number Diff line
@@ -70,6 +70,9 @@ struct mce_log { 
#define MCE_THRESHOLD_BASE      MCE_EXTENDED_BANK + 1 /* MCE_AMD */

#define MCE_THRESHOLD_DRAM_ECC  MCE_THRESHOLD_BASE + 4



#ifdef __KERNEL__

#include <asm/atomic.h>



void mce_log(struct mce *m);

#ifdef CONFIG_X86_MCE_INTEL

void mce_intel_feature_init(struct cpuinfo_x86 *c);
@@ -87,4 +90,8 @@ static inline void mce_amd_feature_init(struct cpuinfo_x86 *c) 
}

#endif



extern atomic_t mce_entry;



#endif



#endif