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authorDon Zickus <dzickus@redhat.com>2010-02-05 21:47:05 -0500
committerIngo Molnar <mingo@elte.hu>2010-02-08 08:29:03 +0100
commit84e478c6f1eb9c4bfa1fff2f8108e9a061b46428 (patch)
tree15be1e0d92d4439e49ecc98a504589dc596fc211
parent1fb9d6ad2766a1dd70d167552988375049a97f21 (diff)
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nmi_watchdog: Config option to enable new nmi_watchdog
These are the bits that enable the new nmi_watchdog and safely isolate the old nmi_watchdog. Only one or the other can run, not both at the same time. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-4-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/kernel/apic/Makefile7
-rw-r--r--arch/x86/kernel/traps.c2
-rw-r--r--include/linux/nmi.h4
-rw-r--r--kernel/Makefile1
-rw-r--r--lib/Kconfig.debug13
5 files changed, 26 insertions, 1 deletions
diff --git a/arch/x86/kernel/apic/Makefile b/arch/x86/kernel/apic/Makefile
index 565c1bfc507..1a4512e48d2 100644
--- a/arch/x86/kernel/apic/Makefile
+++ b/arch/x86/kernel/apic/Makefile
@@ -2,7 +2,12 @@
# Makefile for local APIC drivers and for the IO-APIC code
#
-obj-$(CONFIG_X86_LOCAL_APIC) += apic.o apic_noop.o probe_$(BITS).o ipi.o nmi.o
+obj-$(CONFIG_X86_LOCAL_APIC) += apic.o apic_noop.o probe_$(BITS).o ipi.o
+ifneq ($(CONFIG_NMI_WATCHDOG),y)
+obj-$(CONFIG_X86_LOCAL_APIC) += nmi.o
+endif
+obj-$(CONFIG_NMI_WATCHDOG) += hw_nmi.o
+
obj-$(CONFIG_X86_IO_APIC) += io_apic.o
obj-$(CONFIG_SMP) += ipi.o
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 51ef893ffa6..973cbc4f044 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -406,6 +406,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
== NOTIFY_STOP)
return;
+#ifndef CONFIG_NMI_WATCHDOG
/*
* Ok, so this is none of the documented NMI sources,
* so it must be the NMI watchdog.
@@ -413,6 +414,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
if (nmi_watchdog_tick(regs, reason))
return;
if (!do_nmi_callback(regs, cpu))
+#endif /* !CONFIG_NMI_WATCHDOG */
unknown_nmi_error(reason, regs);
#else
unknown_nmi_error(reason, regs);
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index b752e807add..a42ff0bef70 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -47,4 +47,8 @@ static inline bool trigger_all_cpu_backtrace(void)
}
#endif
+#ifdef CONFIG_NMI_WATCHDOG
+int hw_nmi_is_cpu_stuck(struct pt_regs *);
+#endif
+
#endif
diff --git a/kernel/Makefile b/kernel/Makefile
index 864ff75d65f..8a5abe53eba 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -76,6 +76,7 @@ obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
+obj-$(CONFIG_NMI_WATCHDOG) += nmi_watchdog.o
obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_SECCOMP) += seccomp.o
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 25c3ed594c5..f80b67e72aa 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -170,6 +170,19 @@ config DETECT_SOFTLOCKUP
can be detected via the NMI-watchdog, on platforms that
support it.)
+config NMI_WATCHDOG
+ bool "Detect Hard Lockups with an NMI Watchdog"
+ depends on DEBUG_KERNEL && PERF_EVENTS
+ default y
+ help
+ Say Y here to enable the kernel to use the NMI as a watchdog
+ to detect hard lockups. This is useful when a cpu hangs for no
+ reason but can still respond to NMIs. A backtrace is displayed
+ for reviewing and reporting.
+
+ The overhead should be minimal, just an extra NMI every few
+ seconds.
+
config BOOTPARAM_SOFTLOCKUP_PANIC
bool "Panic (Reboot) On Soft Lockups"
depends on DETECT_SOFTLOCKUP