Commit 6f6b1e04 authored by Fernando Luis Vzquez Cao's avatar Fernando Luis Vzquez Cao Committed by Andi Kleen
Browse files

[PATCH] i386: Disallow kprobes on NMI handlers 



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

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: default avatarFernando Vazquez <fernando@intellilink.co.jp>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent e9dff0ee

arch/i386/kernel/mca.c

+5 −3
Original line number Diff line number Diff line
@@ -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 mca_device *mca_dev, int check_flag) 


/*--------------------------------------------------------------------*/



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(struct device *dev, void *data) 
	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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