[Intel-gfx] [PATCH] drm/i915: fix pm refcounting on fence error in execbuf

[Chris Wilson]

On Fri, Feb 03, 2017 at 02:45:29PM -0800, Daniele Ceraolo Spurio wrote:
> Fences are creted/checked before the pm ref is taken, so if we jump to
> pre_mutex_err we will uncorrectly call intel_runtime_pm_put.
> 
> Fixes: fec0445caa27 (drm/i915: Support explicit fencing for execbuf)
> Testcase: igt/gem_exec_params
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

Sigh. The tree I was using has this:

	if (args->flags & I915_EXEC_FENCE_IN) {
		in_fence = sync_file_get_fence(lower_32_bits(args->rsvd2));
		if (!in_fence)
			return -EINVAL;
	}

	if (args->flags & I915_EXEC_FENCE_OUT) {
		out_fence_fd = get_unused_fd_flags(O_CLOEXEC);
		if (out_fence_fd < 0) {
			ret = out_fence_fd;
			goto err_in_fence;
		}
	}

	...

	err_unlock:
		mutex_unlock(&dev->struct_mutex);
	err_rpm:
		intel_runtime_pm_put(eb.i915);
		eb_destroy(&eb);
		if (out_fence_fd != -1)
			put_unused_fd(out_fence_fd);
	err_in_fence:
		dma_fence_put(in_fence);
		return ret;
	}

Transforming the unwind sequence to match would be appreciated.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre