From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:56492 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751194AbcKQHPI (ORCPT ); Thu, 17 Nov 2016 02:15:08 -0500 Subject: Patch "drm/amdgpu: fix sched fence slab teardown" has been added to the 4.8-stable tree To: notasas@gmail.com, alexander.deucher@amd.com, christian.koenig@amd.com, david1.zhou@amd.com, gregkh@linuxfoundation.org Cc: , From: Date: Thu, 17 Nov 2016 08:15:09 +0100 Message-ID: <1479366909118130@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled drm/amdgpu: fix sched fence slab teardown to the 4.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amdgpu-fix-sched-fence-slab-teardown.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From a053fb7e512c77f0742bceb578b10025256e1911 Mon Sep 17 00:00:00 2001 From: Grazvydas Ignotas Date: Sun, 23 Oct 2016 21:31:44 +0300 Subject: drm/amdgpu: fix sched fence slab teardown MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Grazvydas Ignotas commit a053fb7e512c77f0742bceb578b10025256e1911 upstream. To free fences, call_rcu() is used, which calls amd_sched_fence_free() after a grace period. During teardown, there is no guarantee all callbacks have finished, so sched_fence_slab may be destroyed before all fences have been freed. If we are lucky, this results in some slab warnings, if not, we get a crash in one of rcu threads because callback is called after amdgpu has already been unloaded. Fix it with a rcu_barrier(). Fixes: 189e0fb76304 ("drm/amdgpu: RCU protected amd_sched_fence_release") Acked-by: Chunming Zhou Reviewed-by: Christian König Signed-off-by: Grazvydas Ignotas Signed-off-by: Alex Deucher Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c +++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c @@ -645,6 +645,7 @@ void amd_sched_fini(struct amd_gpu_sched { if (sched->thread) kthread_stop(sched->thread); + rcu_barrier(); if (atomic_dec_and_test(&sched_fence_slab_ref)) kmem_cache_destroy(sched_fence_slab); } Patches currently in stable-queue which might be from notasas@gmail.com are queue-4.8/drm-amdgpu-fix-sched-fence-slab-teardown.patch queue-4.8/drm-amd-fix-scheduler-fence-teardown-order-v2.patch