[tip:x86/urgent] x86/mm/kaslr: Fix -Wformat-security warning

[tip-bot for Nicolas Iooss]

Commit-ID:  62d16b5a3fca4d186e13215e0d7d2f6d36191796
Gitweb:     http://git.kernel.org/tip/62d16b5a3fca4d186e13215e0d7d2f6d36191796
Author:     Nicolas Iooss <nicolas.iooss_linux@xxxxxxx>
AuthorDate: Sat, 6 Aug 2016 12:20:39 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 11 Aug 2016 10:58:12 +0200

x86/mm/kaslr: Fix -Wformat-security warning

debug_putstr() is used to output strings without using printf-like
formatting but debug_putstr(v) is defined as early_printk(v) in
arch/x86/lib/kaslr.c.

This makes clang reports the following warning when building
with -Wformat-security:

    arch/x86/lib/kaslr.c:57:15: warning: format string is not a string
    literal (potentially insecure) [-Wformat-security]
            debug_putstr(purpose);
                         ^~~~~~~

Fix this by using "%s" in early_printk().

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@xxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20160806102039.27221-1-nicolas.iooss_linux@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/lib/kaslr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c
index f7dfeda..121f59c 100644
--- a/arch/x86/lib/kaslr.c
+++ b/arch/x86/lib/kaslr.c
@@ -19,7 +19,7 @@
 #include <asm/cpufeature.h>
 #include <asm/setup.h>
 
-#define debug_putstr(v) early_printk(v)
+#define debug_putstr(v) early_printk("%s", v)
 #define has_cpuflag(f) boot_cpu_has(f)
 #define get_boot_seed() kaslr_offset()
 #endif