From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:42586 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751745AbcKQJpe (ORCPT ); Thu, 17 Nov 2016 04:45:34 -0500 Subject: Patch "drm/amdgpu: fix 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 10:45:37 +0100 Message-ID: <147937593764113@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 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-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 0f10425e811355986907c54f7d1d06703e406092 Mon Sep 17 00:00:00 2001 From: Grazvydas Ignotas Date: Sun, 23 Oct 2016 21:31:43 +0300 Subject: drm/amdgpu: fix fence slab teardown MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Grazvydas Ignotas commit 0f10425e811355986907c54f7d1d06703e406092 upstream. To free fences, call_rcu() is used, which calls amdgpu_fence_free() after a grace period. During teardown, there is no guarantee all callbacks have finished, so amdgpu_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: b44135351a3a ("drm/amdgpu: RCU protected amdgpu_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/amdgpu/amdgpu_fence.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c @@ -68,6 +68,7 @@ int amdgpu_fence_slab_init(void) void amdgpu_fence_slab_fini(void) { + rcu_barrier(); kmem_cache_destroy(amdgpu_fence_slab); } /* Patches currently in stable-queue which might be from notasas@gmail.com are queue-4.8/drm-amdgpu-fix-fence-slab-teardown.patch queue-4.8/drm-amdgpu-fix-sched-fence-slab-teardown.patch queue-4.8/drm-amd-fix-scheduler-fence-teardown-order-v2.patch queue-4.8/drm-amdgpu-fix-a-vm_flush-fence-leak.patch