include, lib: add __printf attributes to several function prototypes

Using __printf attributes helps to detect several format string issues
at compile time (even though -Wformat-security is currently disabled in
Makefile).  For example it can detect when formatting a pointer as a
number, like the issue fixed in commit a3fa71c40f18 ("wl18xx: show
rx_frames_per_rates as an array as it really is"), or when the arguments
do not match the format string, c.f.  for example commit 5ce1aca81435
("reiserfs: fix __RASSERT format string").

To prevent similar bugs in the future, add a __printf attribute to every
function prototype which needs one in include/linux/ and lib/.  These
functions were mostly found by using gcc's -Wsuggest-attribute=format
flag.

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index 5a31bf3a4024..a2b4ea70a946 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -637,8 +637,9 @@ extern int devres_release_group(struct device *dev, void *id);
 
 /* managed devm_k.alloc/kfree for device drivers */
 extern void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp);
-extern char *devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt,
-                             va_list ap);
+extern __printf(3, 0)
+char *devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt,
+                      va_list ap);
 extern __printf(3, 4)
 char *devm_kasprintf(struct device *dev, gfp_t gfp, const char *fmt, ...);
 static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
@@ -1011,12 +1012,10 @@ extern int __must_check device_reprobe(struct device *dev);
 /*
  * Easy functions for dynamically creating devices on the fly
  */
-extern struct device *device_create_vargs(struct class *cls,
-                                          struct device *parent,
-                                          dev_t devt,
-                                          void *drvdata,
-                                          const char *fmt,
-                                          va_list vargs);
+extern __printf(5, 0)
+struct device *device_create_vargs(struct class *cls, struct device *parent,
+                                   dev_t devt, void *drvdata,
+                                   const char *fmt, va_list vargs);
 extern __printf(5, 6)
 struct device *device_create(struct class *cls, struct device *parent,
                              dev_t devt, void *drvdata,