From 65baf0ef046b0297a1214932d48a6b71d3d79b4c Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 18 Mar 2019 09:51:46 +0000 Subject: drm/i915: Hold a ref to the ring while retiring As the final request on a ring may hold the reference to this ring (via retiring the last pinned context), we may find ourselves chasing a dangling pointer on completion of the list. A quick solution is to hold a reference to the ring itself as we retire along it so that we only free it after we stop dereferencing it. Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20190318095204.9913-4-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_request.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/i915/i915_request.c') diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 9533a85cb0b3..0a3d94517d0a 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -1332,8 +1332,12 @@ void i915_retire_requests(struct drm_i915_private *i915) if (!i915->gt.active_requests) return; - list_for_each_entry_safe(ring, tmp, &i915->gt.active_rings, active_link) + list_for_each_entry_safe(ring, tmp, + &i915->gt.active_rings, active_link) { + intel_ring_get(ring); /* last rq holds reference! */ ring_retire_requests(ring); + intel_ring_put(ring); + } } #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) -- cgit v1.2.3