From c0168a3ee6208e72050f47473d9b63fa248ca582 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 10 Dec 2019 15:36:20 +0000 Subject: [PATCH] drm/i915/gt: Check we are the Ironlake IPS provider before deregistering Check that we own the global pointer before deregistering. Reported-by: Venkata Sandeep Dhanalakota Signed-off-by: Chris Wilson Cc: Venkata Sandeep Dhanalakota Cc: Andi Shyti Reviewed-by: Venkata Sandeep Dhanalakota Link: https://patchwork.freedesktop.org/patch/msgid/20191210153620.3929372-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/intel_rps.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c index 08a38a3..fd01e41 100644 --- a/drivers/gpu/drm/i915/gt/intel_rps.c +++ b/drivers/gpu/drm/i915/gt/intel_rps.c @@ -1715,6 +1715,7 @@ void intel_rps_driver_register(struct intel_rps *rps) * set up, to avoid intel-ips sneaking in and reading bogus values. */ if (IS_GEN(gt->i915, 5)) { + GEM_BUG_ON(ips_mchdev); rcu_assign_pointer(ips_mchdev, gt->i915); ips_ping_for_i915_load(); } @@ -1722,7 +1723,8 @@ void intel_rps_driver_register(struct intel_rps *rps) void intel_rps_driver_unregister(struct intel_rps *rps) { - rcu_assign_pointer(ips_mchdev, NULL); + if (ips_mchdev == rps_to_i915(rps)) + rcu_assign_pointer(ips_mchdev, NULL); } static struct drm_i915_private *mchdev_get(void) -- 2.7.4