* Dhaval Giani <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I've been running ftrace on the sched-devel tree. I just built a
> kernel and tried rebooting using kexec and I get this,
hm, it's not a good idea to keep using the data structures of the tracer
while we kexec. Does the patch below resolve the problem?
Ingo
-------------------------->
Subject: x86: patches/ftrace-kexec-fix.patch
From: Ingo Molnar <[EMAIL PROTECTED]>
Date: Tue Feb 19 15:13:56 CET 2008
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
---
arch/x86/kernel/machine_kexec_32.c | 4 ++++
arch/x86/kernel/machine_kexec_64.c | 4 ++++
include/linux/ftrace.h | 7 +++++++
3 files changed, 15 insertions(+)
Index: linux/arch/x86/kernel/machine_kexec_32.c
===================================================================
--- linux.orig/arch/x86/kernel/machine_kexec_32.c
+++ linux/arch/x86/kernel/machine_kexec_32.c
@@ -11,6 +11,8 @@
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/numa.h>
+#include <linux/ftrace.h>
+
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
@@ -107,6 +109,8 @@ NORET_TYPE void machine_kexec(struct kim
unsigned long page_list[PAGES_NR];
void *control_page;
+ tracer_disable();
+
/* Interrupts aren't acceptable while we reboot */
local_irq_disable();
Index: linux/arch/x86/kernel/machine_kexec_64.c
===================================================================
--- linux.orig/arch/x86/kernel/machine_kexec_64.c
+++ linux/arch/x86/kernel/machine_kexec_64.c
@@ -11,6 +11,8 @@
#include <linux/string.h>
#include <linux/reboot.h>
#include <linux/numa.h>
+#include <linux/ftrace.h>
+
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
@@ -184,6 +186,8 @@ NORET_TYPE void machine_kexec(struct kim
unsigned long page_list[PAGES_NR];
void *control_page;
+ tracer_disable();
+
/* Interrupts aren't acceptable while we reboot */
local_irq_disable();
Index: linux/include/linux/ftrace.h
===================================================================
--- linux.orig/include/linux/ftrace.h
+++ linux/include/linux/ftrace.h
@@ -68,6 +68,13 @@ extern void ftrace_call(void);
extern void mcount_call(void);
#endif
+static inline void tracer_disable(void)
+{
+#ifdef CONFIG_FTRACE
+ ftrace_enabled = 0;
+#endif
+}
+
#ifdef CONFIG_FRAME_POINTER
/* TODO: need to fix this for ARM */
# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
--
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