diff -Naur -p -X /home/marcelo/lib/dontdiff linux-2.4.26/arch/i386/kernel/mtrr.c linux-2.4.27-rc5/arch/i386/kernel/mtrr.c
--- linux-2.4.26/arch/i386/kernel/mtrr.c	2003-06-13 14:51:29.000000000 +0000
+++ linux-2.4.27-rc5/arch/i386/kernel/mtrr.c	2004-08-03 23:05:06.000000000 +0000
@@ -1648,11 +1648,17 @@ static int mtrr_file_del (unsigned long 
 static ssize_t mtrr_read (struct file *file, char *buf, size_t len,
 			  loff_t *ppos)
 {
-    if (*ppos >= ascii_buf_bytes) return 0;
-    if (*ppos + len > ascii_buf_bytes) len = ascii_buf_bytes - *ppos;
-    if ( copy_to_user (buf, ascii_buffer + *ppos, len) ) return -EFAULT;
-    *ppos += len;
-    return len;
+	loff_t pos = *ppos;
+	if (pos < 0 || pos >= ascii_buf_bytes)
+		return 0;
+	if (len > ascii_buf_bytes - pos)
+		len = ascii_buf_bytes - pos;
+	if (copy_to_user(buf, ascii_buffer + pos, len))
+		return -EFAULT;
+	pos += len;
+	*ppos = pos;
+
+	return len;
 }   /*  End Function mtrr_read  */
 
 static ssize_t mtrr_write (struct file *file, const char *buf, size_t len,