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SubjectRe: [PATCH] x86: nmi - fix incorrect NMI watchdog used by default
[Ingo Molnar - Fri, May 30, 2008 at 02:54:00PM +0200]
|
| * Cyrill Gorcunov <gorcunov@gmail.com> wrote:
|
| > +extern void nmi_watchdog_default(void);
| > +#else
| > +#define nmi_watchdog_default(void) do {} while (0)
| ^------
|
| that doesnt work too well in a macro ... :-)
|
| Ingo
|

Oh my.... maybe two prerocessor passes would help? ;-)
here is an updated version, please reapply, and thanks a lot
for catching this Ingo! Sorry for inconvenience.
- Cyrill -
---
Subject: [PATCH] x86: nmi - fix incorrect NMI watchdog used by default

Commit

commit 4b82b277707a39b97271439c475f186f63ec4692
Author: Cyrill Gorcunov <gorcunov@gmail.com>
Date: Sat May 24 19:36:35 2008 +0400

sets nmi_watchdog to NMI_IO_APIC as by default value
even not being asking to. That 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: Cyrill Gorcunov <gorcunov@gmail.com>
CC: Maciej W. Rozycki <macro@linux-mips.org>
---
Index: linux-2.6.git/arch/x86/kernel/nmi.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/nmi.c 2008-05-28 22:32:38.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/nmi.c 2008-05-28 22:40:48.000000000 +0400
@@ -84,20 +84,15 @@ static inline unsigned int get_timer_irq
#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 *t
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)
Index: linux-2.6.git/include/asm-x86/nmi.h
====================================================================
--- linux-2.6.git.orig/include/asm-x86/nmi.h 2008-05-28 22:32:41.000000000 +0400
+++ linux-2.6.git/include/asm-x86/nmi.h 2008-05-28 22:39:55.000000000 +0400
@@ -38,9 +38,11 @@ static inline void unset_nmi_pm_callback

#ifdef CONFIG_X86_64
extern void default_do_nmi(struct pt_regs *);
+extern void nmi_watchdog_default(void);
+#else
+#define nmi_watchdog_default() 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;

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