From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Commit 3b3f1650b1ca ("drm/i915: Allocate intel_engine_cs
structure only for the enabled engines") introduced the
dynanically allocated engine instances and created an
potential use after free scenario in logical_render_ring_init
where lrc_destroy_wa_ctx_obj could be called after the engine
instance has been freed.
This can only happen during engine setup/init error handling
which luckily does not happen ever in practice.
Fix is to not call lrc_destroy_wa_ctx_obj since it would have
already been executed from the preceding engine cleanup.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Fixes: 3b3f1650b1ca ("drm/i915: Allocate intel_engine_cs structure only for the enabled engines")
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_lrc.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 8b412880e88c..877adedbf833 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1965,12 +1965,7 @@ int logical_render_ring_init(struct intel_engine_cs *engine)
ret);
}
- ret = logical_ring_init(engine);
- if (ret) {
- lrc_destroy_wa_ctx_obj(engine);
- }
-
- return ret;
+ return logical_ring_init(engine);
}
int logical_xcs_ring_init(struct intel_engine_cs *engine)
--
2.7.4
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