On Tue, Nov 17, 2015 at 01:04:21PM +0200, Ville Syrjälä wrote:
On Tue, Nov 17, 2015 at 10:47:06AM +0100, Daniel Vetter wrote:
On Wed, Nov 11, 2015 at 07:11:28PM +0200, ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@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: stable@vger.kernel.org Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Fixes: 2a80eada326f ("drm/i915: Add fb format modifier support") Testcase: igt/kms_addfb_basic/clobbered-modifier Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
Out of curiosity: Where does this blow up? That should be added to the commit message (so that people affected can match it up with this fix).
I don't know that it affects any actual users. The way I caught this was running kms_addfb_basic. One of the subtests failed when I ran the full test, but if I ran only the specific subtest it was fine. So the modifiers got clobbered by the previous subtest. I already forgot which subtest it was, but it's easy enough to track it down again.
# ./tests/kms_addfb_basic IGT-Version: 1.12-git (x86_64) (Linux: 4.4.0-rc1-stereo+ x86_64) ... Subtest basic-X-tiled: SUCCESS (0.001s) Test assertion failure function pitch_tests, file kms_addfb_basic.c:167: Failed assertion: drmIoctl(fd, DRM_IOCTL_MODE_ADDFB2, &f) == 0 Last errno: 22, Invalid argument Stack trace: #0 [__igt_fail_assert+0x101] #1 [pitch_tests+0x619] #2 [__real_main426+0x2f] #3 [main+0x23] #4 [__libc_start_main+0xf0] #5 [_start+0x29] #6 [<unknown>+0x29] Subtest framebuffer-vs-set-tiling failed. **** DEBUG **** Test assertion failure function pitch_tests, file kms_addfb_basic.c:167: Failed assertion: drmIoctl(fd, DRM_IOCTL_MODE_ADDFB2, &f) == 0 Last errno: 22, Invalid argument **** END **** Subtest framebuffer-vs-set-tiling: FAIL (0.003s) ...
# ./tests/kms_addfb_basic --r framebuffer-vs-set-tiling IGT-Version: 1.12-git (x86_64) (Linux: 4.4.0-rc1-stereo+ x86_64) Subtest framebuffer-vs-set-tiling: SUCCESS (0.000s)
With that:
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
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]));
- 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
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
-- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx