[PATCH 2/2] i386: Disallow kprobes on NMI handlers

From: Fernando Luis Vázquez Cao
Date: Thu Aug 10 2006 - 06:34:32 EST

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

Note: This problem was originally identified by Andi Kleen. This patch
adds fixes not included in his original patch.

Signed-off-by: Fernando Vazquez <fernando@xxxxxxxxxxxxxxxxx>

diff -urNp linux-2.6.18-rc4-orig/arch/i386/kernel/mca.c linux-2.6.18-rc4/arch/i386/kernel/mca.c
--- linux-2.6.18-rc4-orig/arch/i386/kernel/mca.c 2006-08-10 17:24:15.000000000 +0900
+++ linux-2.6.18-rc4/arch/i386/kernel/mca.c 2006-08-10 19:34:37.000000000 +0900
@@ -414,7 +414,8 @@ 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 +445,7 @@ 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 +463,7 @@ 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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