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, 3 insertions, 3 deletions

diff --git a/include/linux/printk.h b/include/linux/printk.h
index 58b1fec40d37..a6298b27ac99 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -122,7 +122,7 @@ static inline __printf(1, 2) __cold
 void early_printk(const char *s, ...) { }
 #endif
 
-typedef int(*printk_func_t)(const char *fmt, va_list args);
+typedef __printf(1, 0) int (*printk_func_t)(const char *fmt, va_list args);
 
 #ifdef CONFIG_PRINTK
 asmlinkage __printf(5, 0)
@@ -166,7 +166,7 @@ char *log_buf_addr_get(void);
 u32 log_buf_len_get(void);
 void log_buf_kexec_setup(void);
 void __init setup_log_buf(int early);
-void dump_stack_set_arch_desc(const char *fmt, ...);
+__printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
 void dump_stack_print_info(const char *log_lvl);
 void show_regs_print_info(const char *log_lvl);
 #else
@@ -217,7 +217,7 @@ static inline void setup_log_buf(int early)
 {
 }
 
-static inline void dump_stack_set_arch_desc(const char *fmt, ...)
+static inline __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...)
 {
 }