lkdtm: fix false positive warning from -Wmaybe-uninitialized

The variable in use here doesn't matter (it's just used to exercise taking
up stack space), but this changes its use to pass its address instead,
to avoid a compiler warning:

drivers/misc/lkdtm_usercopy.c:54:15: warning: 'bad_stack' may be used uninitialized in this function [-Wmaybe-uninitialized]

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/drivers/misc/lkdtm_usercopy.c b/drivers/misc/lkdtm_usercopy.c
index 5a3fd76..5525a20 100644 (file)
--- a/drivers/misc/lkdtm_usercopy.c
+++ b/drivers/misc/lkdtm_usercopy.c
@@ -49,7 +49,7 @@ static noinline void do_usercopy_stack(bool to_user, bool bad_frame)
 
        /* This is a pointer to outside our current stack frame. */
        if (bad_frame) {
-               bad_stack = do_usercopy_stack_callee((uintptr_t)bad_stack);
+               bad_stack = do_usercopy_stack_callee((uintptr_t)&bad_stack);
        } else {
                /* Put start address just inside stack. */
                bad_stack = task_stack_page(current) + THREAD_SIZE;