* [PATCH] x86: fix trigger_all_cpu_backtrace() implementation
@ 2013-06-06 11:41 Michel Lespinasse
2013-06-20 12:00 ` Ingo Molnar
2013-06-20 14:48 ` [tip:x86/urgent] x86: Fix " tip-bot for Michel Lespinasse
0 siblings, 2 replies; 3+ messages in thread
From: Michel Lespinasse @ 2013-06-06 11:41 UTC (permalink / raw)
To: Linus Torvalds, Thomas Gleixner, Ingo Molnar, H. Peter Anvin
Cc: Andrew Morton, linux-kernel, x86
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] x86: fix trigger_all_cpu_backtrace() implementation
2013-06-06 11:41 [PATCH] x86: fix trigger_all_cpu_backtrace() implementation Michel Lespinasse
@ 2013-06-20 12:00 ` Ingo Molnar
2013-06-20 14:48 ` [tip:x86/urgent] x86: Fix " tip-bot for Michel Lespinasse
1 sibling, 0 replies; 3+ messages in thread
From: Ingo Molnar @ 2013-06-20 12:00 UTC (permalink / raw)
To: Michel Lespinasse
Cc: Linus Torvalds, Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
Andrew Morton, linux-kernel, x86
* Michel Lespinasse <walken@google.com> wrote:
> 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 ?
Looks good at first glance - I'll test it and push Linuswards.
Thanks,
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
* [tip:x86/urgent] x86: Fix trigger_all_cpu_backtrace() implementation
2013-06-06 11:41 [PATCH] x86: fix trigger_all_cpu_backtrace() implementation Michel Lespinasse
2013-06-20 12:00 ` Ingo Molnar
@ 2013-06-20 14:48 ` tip-bot for Michel Lespinasse
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Michel Lespinasse @ 2013-06-20 14:48 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, torvalds, tglx, walken
Commit-ID: b52e0a7c4e4100f8683af508664e60e1603070f9
Gitweb: http://git.kernel.org/tip/b52e0a7c4e4100f8683af508664e60e1603070f9
Author: Michel Lespinasse <walken@google.com>
AuthorDate: Thu, 6 Jun 2013 04:41:15 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 20 Jun 2013 14:00:21 +0200
x86: Fix trigger_all_cpu_backtrace() implementation
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.
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 via: 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>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1370518875-1346-1-git-send-email-walken@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
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 ba870bb..57873be 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 c0fa356..86f9301 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 31cb9ae..a698d71 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>
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2013-06-06 11:41 [PATCH] x86: fix trigger_all_cpu_backtrace() implementation Michel Lespinasse
2013-06-20 12:00 ` Ingo Molnar
2013-06-20 14:48 ` [tip:x86/urgent] x86: Fix " tip-bot for Michel Lespinasse
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