[PATCH for review] [144/145] i386: Disallow kprobes on NMI handlers

From: Andi Kleen
Date: Thu Aug 10 2006 - 15:40:23 EST


From: Fernando Luis =?ISO-8859-1?Q?V=E1zquez?= Cao <fernando@xxxxxxxxxxxxx>

A kprobe executes IRET early and that could cause NMI recursion and stack

Note: This problem was originally spotted by Andi Kleen. This patch
adds fixes not included in his original patch.
[AK: Jan Beulich originally discovered these classes of bugs]

Signed-off-by: Fernando Vazquez <fernando@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxx>


arch/i386/kernel/mca.c | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)

Index: linux/arch/i386/kernel/mca.c
--- linux.orig/arch/i386/kernel/mca.c
+++ linux/arch/i386/kernel/mca.c
@@ -42,6 +42,7 @@
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mca.h>
+#include <linux/kprobes.h>
#include <asm/system.h>
#include <asm/io.h>
#include <linux/proc_fs.h>
@@ -414,7 +415,8 @@ subsys_initcall(mca_init);


-static void mca_handle_nmi_device(struct mca_device *mca_dev, int check_flag)
+static __kprobes void
+mca_handle_nmi_device(struct mca_device *mca_dev, int check_flag)
int slot = mca_dev->slot;

@@ -444,7 +446,7 @@ static void mca_handle_nmi_device(struct


-static int mca_handle_nmi_callback(struct device *dev, void *data)
+static int __kprobes mca_handle_nmi_callback(struct device *dev, void *data)
struct mca_device *mca_dev = to_mca_device(dev);
unsigned char pos5;
@@ -462,7 +464,7 @@ static int mca_handle_nmi_callback(struc
return 0;

-void mca_handle_nmi(void)
+void __kprobes mca_handle_nmi(void)
/* First try - scan the various adapters and see if a specific
* adapter was responsible for the error.
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