um: fix _FORTIFY_SOURCE=2 support for kernel modules

When UML is compiled with _FORTIFY_SOURCE we have to export all _chk()
functions which are used in modules.  For now it's only the case for
__sprintf_chk().

Tested-by: Florian Fainelli <florian@openwrt.org>
Reported-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/um/os-Linux/user_syms.c b/arch/um/os-Linux/user_syms.c
index 05f5ea8e83d2ab211e4dfc27b6be2a458da59e74..45ffe46871e0528e388ff58aa264694647c06235 100644 (file)
--- a/arch/um/os-Linux/user_syms.c
+++ b/arch/um/os-Linux/user_syms.c
@@ -113,3 +113,8 @@ EXPORT_SYMBOL(__stack_smash_handler);
 
 extern long __guard __attribute__((weak));
 EXPORT_SYMBOL(__guard);
+
+#ifdef _FORTIFY_SOURCE
+extern int __sprintf_chk(char *str, int flag, size_t strlen, const char *format);
+EXPORT_SYMBOL(__sprintf_chk);
+#endif