[Intel-gfx] [PATCH] drm/i915/selftests: Fix i915_address_space refcnt leak

[Chris Wilson]

Quoting Xiyu Yang (2020-04-20 06:41:54)
> igt_ppgtt_pin_update() invokes i915_gem_context_get_vm_rcu(), which
> returns a reference of the i915_address_space object to "vm" with
> increased refcount.
> 
> When igt_ppgtt_pin_update() returns, "vm" becomes invalid, so the
> refcount should be decreased to keep refcount balanced.
> 
> The reference counting issue happens in two exception handling paths of
> igt_ppgtt_pin_update(). When i915_gem_object_create_internal() returns
> IS_ERR, the refcnt increased by i915_gem_context_get_vm_rcu() is not
> decreased, causing a refcnt leak.
> 
> Fix this issue by jumping to "out_vm" label when
> i915_gem_object_create_internal() returns IS_ERR.
> 
> Fixes: 4049866f0913 ("drm/i915/selftests: huge page tests")

Actually,
Fixes: a4e7ccdac38e ("drm/i915: Move context management under GEM")

> Signed-off-by: Xiyu Yang <xiyuyang19 at fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf at gmail.com>

Other than that,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris