[PATCH 4.4 003/137] parisc: Avoid function pointers for kernel exception routines

From: Greg Kroah-Hartman
Date: Sun Apr 17 2016 - 22:34:52 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Helge Deller <deller@xxxxxx>

commit e3893027a300927049efc1572f852201eb785142 upstream.

We want to avoid the kernel module loader to create function pointers
for the kernel fixup routines of get_user() and put_user(). Changing
the external reference from function type to int type fixes this.

This unbreaks exception handling for get_user() and put_user() when
called from a kernel module.

Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/parisc/kernel/parisc_ksyms.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/arch/parisc/kernel/parisc_ksyms.c
+++ b/arch/parisc/kernel/parisc_ksyms.c
@@ -47,11 +47,11 @@ EXPORT_SYMBOL(__cmpxchg_u64);
EXPORT_SYMBOL(lclear_user);
EXPORT_SYMBOL(lstrnlen_user);

-/* Global fixups */
-extern void fixup_get_user_skip_1(void);
-extern void fixup_get_user_skip_2(void);
-extern void fixup_put_user_skip_1(void);
-extern void fixup_put_user_skip_2(void);
+/* Global fixups - defined as int to avoid creation of function pointers */
+extern int fixup_get_user_skip_1;
+extern int fixup_get_user_skip_2;
+extern int fixup_put_user_skip_1;
+extern int fixup_put_user_skip_2;
EXPORT_SYMBOL(fixup_get_user_skip_1);
EXPORT_SYMBOL(fixup_get_user_skip_2);
EXPORT_SYMBOL(fixup_put_user_skip_1);