On 06/20/2017 01:49 PM, Serge E. Hallyn wrote:

Quoting Arnd Bergmann (arnd at arndb.de):

quoted

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@arndb.de>

Acked-by: Serge Hallyn <serge@hallyn.com>

Acked-by: John Johansen <john.johansen@canonical.com>

quoted

--
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)
 #else
-#define AA_BUG_FMT(X, fmt, args...)
+#define AA_BUG_FMT(X, fmt, args...) no_printk("%s" fmt, __func__, ##args)
 #endif
 
 #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);
 remove:

-- 
2.9.0

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