From: Michel Lespinasse <walken@google.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, x86@kernel.org
Subject: [PATCH] x86: fix trigger_all_cpu_backtrace() implementation
Date: Thu, 6 Jun 2013 04:41:15 -0700 [thread overview]
Message-ID: <1370518875-1346-1-git-send-email-walken@google.com> (raw)
The following change fixes the x86 implementation of
trigger_all_cpu_backtrace(), which was previously (accidentally, as
far as I can tell) disabled to always return false as on architectures
that do not implement this function.
Is there any chance that we could get this in before v3.10 ?
---------------------------------8<---------------------------------
trigger_all_cpu_backtrace(), as defined in include/linux/nmi.h,
should call arch_trigger_all_cpu_backtrace() if available, or return
false if the underlying arch doesn't implement this function.
x86 did provide a suitable arch_trigger_all_cpu_backtrace() implementation,
but it wasn't actually being used because it was declared in asm/nmi.h,
which linux/nmi.h doesn't include. Also, linux/nmi.h couldn't easily
be fixed by including asm/nmi.h, because that file is not available on
all architectures.
I am proposing to fix this by moving the x86 definition of
arch_trigger_all_cpu_backtrace() to asm/irq.h.
Tested: echo l > /proc/sysrq-trigger
Before the change, this uses a fallback implementation which shows
backtraces on active CPUs (using smp_call_function_interrupt() )
After the change, this shows NMI backtraces on all CPUs
Signed-off-by: Michel Lespinasse <walken@google.com>
---
arch/x86/include/asm/irq.h | 5 +++++
arch/x86/include/asm/nmi.h | 4 +---
arch/x86/kernel/apic/hw_nmi.c | 1 +
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index ba870bb6dd8e..57873beb3292 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -41,4 +41,9 @@ extern int vector_used_by_percpu_irq(unsigned int vector);
extern void init_ISA_irqs(void);
+#ifdef CONFIG_X86_LOCAL_APIC
+void arch_trigger_all_cpu_backtrace(void);
+#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
+#endif
+
#endif /* _ASM_X86_IRQ_H */
diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h
index c0fa356e90de..86f9301903c8 100644
--- a/arch/x86/include/asm/nmi.h
+++ b/arch/x86/include/asm/nmi.h
@@ -18,9 +18,7 @@ extern int proc_nmi_enabled(struct ctl_table *, int ,
void __user *, size_t *, loff_t *);
extern int unknown_nmi_panic;
-void arch_trigger_all_cpu_backtrace(void);
-#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
-#endif
+#endif /* CONFIG_X86_LOCAL_APIC */
#define NMI_FLAG_FIRST 1
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 31cb9ae992b7..a698d7165c96 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -9,6 +9,7 @@
*
*/
#include <asm/apic.h>
+#include <asm/nmi.h>
#include <linux/cpumask.h>
#include <linux/kdebug.h>
--
1.8.3
next reply other threads:[~2013-06-06 11:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-06 11:41 Michel Lespinasse [this message]
2013-06-20 12:00 ` [PATCH] x86: fix trigger_all_cpu_backtrace() implementation Ingo Molnar
2013-06-20 14:48 ` [tip:x86/urgent] x86: Fix " tip-bot for Michel Lespinasse
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