commit 0083b63a10a5661ea6f167f4732cd6fb8c35b94b
Author: Alexander Korolkov <alexander.korolkov@gmail.com>
Date:   Sun Oct 23 01:38:35 2011 +0400

    Race condition

diff --git a/linuxkernel/linux-2.6.27/arch/arm/include/asm/system.h b/linuxkernel/linux-2.6.27/arch/arm/include/asm/system.h
index 514af79..708be12 100644
--- a/linuxkernel/linux-2.6.27/arch/arm/include/asm/system.h
+++ b/linuxkernel/linux-2.6.27/arch/arm/include/asm/system.h
@@ -265,7 +265,10 @@ extern struct task_struct *__switch_to(struct task_struct *, struct thread_info
 
 #define switch_to(prev,next,last)					\
 do {									\
+	unsigned long __iflags;						\
+	local_irq_save(__iflags);					\
 	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));	\
+	local_irq_restore(__iflags);					\
 } while (0)
 
 #if defined(CONFIG_CPU_SA1100) || defined(CONFIG_CPU_SA110)
diff --git a/linuxkernel/linux-2.6.27/arch/arm/include/asm/uaccess.h b/linuxkernel/linux-2.6.27/arch/arm/include/asm/uaccess.h
index d0f51ff..b754116 100644
--- a/linuxkernel/linux-2.6.27/arch/arm/include/asm/uaccess.h
+++ b/linuxkernel/linux-2.6.27/arch/arm/include/asm/uaccess.h
@@ -60,8 +60,11 @@ extern int __put_user_bad(void);
 
 static inline void set_fs(mm_segment_t fs)
 {
+	unsigned long flags;
+	local_irq_save(flags);
 	current_thread_info()->addr_limit = fs;
 	modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
+	local_irq_restore(flags);
 }
 
 #define segment_eq(a,b)	((a) == (b))