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authorIngo Molnar <mingo@elte.hu>2007-03-05 13:20:11 +0100
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-03-05 08:23:51 -0800
commit6ebf622b2577c50b1f496bd6a5e8739e55ae7b1c (patch)
treeae4da73844c08c9cfc6e934eabc55c1fb1188845
parent0d05ad2c09af9fb33ae76f9f8d1c4e4d1a9de92c (diff)
[PATCH] disable NMI watchdog by default
there's a new NMI watchdog related problem: KVM crashes on certain bzImages because ... we enable the NMI watchdog by default (even if the user does not ask for it) , and no other OS on this planet does that so KVM doesnt have emulation for that yet. So KVM injects a #GP, which crashes the Linux guest: general protection fault: 0000 [#1] PREEMPT SMP Modules linked in: CPU: 0 EIP: 0060:[<c011a8ae>] Not tainted VLI EFLAGS: 00000246 (2.6.20-rc5-rt0 #3) EIP is at setup_apic_nmi_watchdog+0x26d/0x3d3 and no, i did /not/ request an nmi_watchdog on the boot command line! Solution: turn off that darn thing! It's a debug tool, not a 'make life harder' tool!! with this patch the KVM guest boots up just fine. And with this my laptop (Lenovo T60) also stopped its sporadic hard hanging (sometimes in acpi_init(), sometimes later during bootup, sometimes much later during actual use) as well. It hung with both nmi_watchdog=1 and nmi_watchdog=2, so it's generally the fact of NMI injection that is causing problems, not the NMI watchdog variant, nor any particular bootup code. [ NMI breaks on some systems, esp in combination with SMM -Arjan ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/asm-i386/nmi.h2
-rw-r--r--include/asm-x86_64/nmi.h2
2 files changed, 2 insertions, 2 deletions
diff --git a/include/asm-i386/nmi.h b/include/asm-i386/nmi.h
index b04333ea6f31..64544cb85d6a 100644
--- a/include/asm-i386/nmi.h
+++ b/include/asm-i386/nmi.h
@@ -33,7 +33,7 @@ extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason);
extern atomic_t nmi_active;
extern unsigned int nmi_watchdog;
-#define NMI_DEFAULT -1
+#define NMI_DEFAULT 0
#define NMI_NONE 0
#define NMI_IO_APIC 1
#define NMI_LOCAL_APIC 2
diff --git a/include/asm-x86_64/nmi.h b/include/asm-x86_64/nmi.h
index 72375e7d32a8..ceb3d8dac33d 100644
--- a/include/asm-x86_64/nmi.h
+++ b/include/asm-x86_64/nmi.h
@@ -64,7 +64,7 @@ extern int setup_nmi_watchdog(char *);
extern atomic_t nmi_active;
extern unsigned int nmi_watchdog;
-#define NMI_DEFAULT -1
+#define NMI_DEFAULT 0
#define NMI_NONE 0
#define NMI_IO_APIC 1
#define NMI_LOCAL_APIC 2