[PATCH v2] apparmor: add braces around optional statement

From: Arnd Bergmann
Date: Tue Jun 20 2017 - 16:47:35 EST

We get a warning when AA_BUG() compiles to an nothing:

security/apparmor/label.c: In function '__label_update':
security/apparmor/label.c:2055:3: error: suggest braces around empty body in an 'else' statement [-Werror=empty-body]

There are two things we can do about this:

- add the missing braces in the call site, which also
brings the code in line with the regular Linux coding style

- redefine the macro so it is not empty but instead uses
no_printk() in AA_BUG_FMT() to perform format checking.

Both seem like good ideas, so this does both at once.

Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
v2: actually include the second part of the patch
security/apparmor/include/lib.h | 2 +-
security/apparmor/label.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/security/apparmor/include/lib.h b/security/apparmor/include/lib.h
index 436b3a722357..cbfb71c1ec88 100644
--- a/security/apparmor/include/lib.h
+++ b/security/apparmor/include/lib.h
@@ -50,7 +50,7 @@
#define AA_BUG_FMT(X, fmt, args...) \
WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
-#define AA_BUG_FMT(X, fmt, args...)
+#define AA_BUG_FMT(X, fmt, args...) no_printk("%s" fmt, __func__, ##args)

#define AA_ERROR(fmt, args...) \
diff --git a/security/apparmor/label.c b/security/apparmor/label.c
index e052eaba1cf6..f8e08d94a8a6 100644
--- a/security/apparmor/label.c
+++ b/security/apparmor/label.c
@@ -2051,8 +2051,9 @@ static struct aa_label *__label_update(struct aa_label *label)
write_lock_irqsave(&ls->lock, flags);
goto remove;
- } else
+ } else {
AA_BUG(labels_ns(label) != labels_ns(new));
+ }

tmp = __label_insert(labels_set(label), new, true);