We need to ensure that we always serialize updates to the bottom-half using the breadcrumbs.irq_lock so that we don't race with a concurrent interrupt handler. This is most important just prior to leaving the waiter (when the intel_wait will be overwritten), so make sure we are not the current bottom-half when skipping the irq locks.
Signed-off-by: Chris Wilson <[email protected]> Cc: Tvrtko Ursulin <[email protected]> --- drivers/gpu/drm/i915/intel_breadcrumbs.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c index ebcb595001fc..d10148567dbc 100644 --- a/drivers/gpu/drm/i915/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c @@ -287,6 +287,7 @@ static inline void __intel_breadcrumbs_finish(struct intel_breadcrumbs *b, struct intel_wait *wait) { lockdep_assert_held(&b->rb_lock); + GEM_BUG_ON(b->irq_wait == wait); /* This request is completed, so remove it from the tree, mark it as * complete, and *then* wake up the associated task. @@ -517,8 +518,10 @@ void intel_engine_remove_wait(struct intel_engine_cs *engine, * the tree by the bottom-half to avoid contention on the spinlock * by the herd. */ - if (RB_EMPTY_NODE(&wait->node)) + if (RB_EMPTY_NODE(&wait->node)) { + GEM_BUG_ON(READ_ONCE(b->irq_wait) == wait); return; + } spin_lock_irq(&b->rb_lock); __intel_engine_remove_wait(engine, wait); -- 2.11.0 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
