[RFC] [PATCH] Refuse kprobe insertion on add/sub_preempt_counter()

From: Srinivasa Ds
Date: Wed Feb 20 2008 - 05:15:35 EST


Kprobes makes use of preempt_disable(),preempt_enable_noresched() and these
functions inturn call add/sub_preempt_count(). So we need to refuse user from
inserting probe in to these functions.

This patch disallows user from probing add/sub_preempt_count().

Signed-off-by: Srinivasa DS <srinivasa@xxxxxxxxxx>


---
kernel/sched.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6.25-rc2/kernel/sched.c
===================================================================
--- linux-2.6.25-rc2.orig/kernel/sched.c
+++ linux-2.6.25-rc2/kernel/sched.c
@@ -3766,7 +3766,7 @@ void scheduler_tick(void)

#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)

-void add_preempt_count(int val)
+void __kprobes add_preempt_count(int val)
{
/*
* Underflow?
@@ -3782,7 +3782,7 @@ void add_preempt_count(int val)
}
EXPORT_SYMBOL(add_preempt_count);

-void sub_preempt_count(int val)
+void __kprobes sub_preempt_count(int val)
{
/*
* Underflow?


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