diff --git a/lib/libstand/stand.h b/lib/libstand/stand.h
index bf4ed289bba..219b2df4697 100644
--- a/lib/libstand/stand.h
+++ b/lib/libstand/stand.h
@@ -369,7 +369,7 @@ extern int		ischar(void);
 extern void		putchar(int);
 extern int		devopen(struct open_file *, const char *, const char **);
 extern int		devclose(struct open_file *f);
-extern void		panic(const char *, ...) __dead2;
+extern void		panic(const char *, ...) __dead2 __printflike(1, 2);
 extern struct fs_ops	*file_system[];
 extern struct devsw	*devsw[];
 
diff --git a/lib/libstand/zalloc_malloc.c b/lib/libstand/zalloc_malloc.c
index cd89d055c4f..fcc54dc71dd 100644
--- a/lib/libstand/zalloc_malloc.c
+++ b/lib/libstand/zalloc_malloc.c
@@ -109,7 +109,7 @@ Free(void *ptr, const char *file, int line)
 	    return;
 	}
 	if (res->ga_Magic != GAMAGIC)
-	    panic("free: guard1 fail @ %p from %s:%p", ptr, file, line);
+	    panic("free: guard1 fail @ %p from %s:%d", ptr, file, line);
 	res->ga_Magic = GAFREE;
 #endif
 #ifdef USEENDGUARD