drm/i915: restrict kernel address leak in debugfs

commit 2563a452 upstream.

Masks kernel address info-leak in object dumps with the %pK suffix,
so they cannot be used to target kernel memory corruption attacks if
the kptr_restrict sysctl is set.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[bwh: Backported to 3.2: the rest of the format string is different]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -122,7 +122,7 @@ static const char *cache_level_str(int type)
 static void
 describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 {
-	seq_printf(m, "%p: %s%s %8zd %04x %04x %d %d%s%s%s",
+	seq_printf(m, "%pK: %s%s %8zd %04x %04x %d %d%s%s%s",
 		   &obj->base,
 		   get_pin_flag(obj),
 		   get_tiling_flag(obj),