From: Ville Syrjälä <ville.syrj...@linux.intel.com>

We try to convert the old way of of specifying fb tiling (obj->tiling)
into the new fb modifiers. We store the result in the passed in mode_cmd
structure. But that structure comes directly from the addfb2 ioctl, and
gets copied back out to userspace, which means we're clobbering the
modifiers that the user provided (all 0 since the DRM_MODE_FB_MODIFIERS
flag wasn't even set by the user). Hence if the user reuses the struct
for another addfb2, the ioctl will be rejected since it's now asking for
some modifiers w/o the flag set.

Fix the problem by making a copy of the user provided structure. We can
play any games we want with the copy.

Cc: sta...@vger.kernel.org
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursu...@intel.com>
Fixes: 2a80eada326f ("drm/i915: Add fb format modifier support")
Testcase: igt/kms_addfb_basic/clobbered-modifier
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c 
b/drivers/gpu/drm/i915/intel_display.c
index b5f7493..c3aa6f5 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -14578,17 +14578,18 @@ static int intel_framebuffer_init(struct drm_device 
*dev,
 static struct drm_framebuffer *
 intel_user_framebuffer_create(struct drm_device *dev,
                              struct drm_file *filp,
-                             struct drm_mode_fb_cmd2 *mode_cmd)
+                             struct drm_mode_fb_cmd2 *user_mode_cmd)
 {
        struct drm_framebuffer *fb;
        struct drm_i915_gem_object *obj;
+       struct drm_mode_fb_cmd2 mode_cmd = *user_mode_cmd;
 
        obj = to_intel_bo(drm_gem_object_lookup(dev, filp,
-                                               mode_cmd->handles[0]));
+                                               mode_cmd.handles[0]));
        if (&obj->base == NULL)
                return ERR_PTR(-ENOENT);
 
-       fb = intel_framebuffer_create(dev, mode_cmd, obj);
+       fb = intel_framebuffer_create(dev, &mode_cmd, obj);
        if (IS_ERR(fb))
                drm_gem_object_unreference_unlocked(&obj->base);
 
-- 
2.4.10

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