From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7C5CC28CC2 for ; Thu, 30 May 2019 03:51:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1E3424D9B for ; Thu, 30 May 2019 03:51:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559188284; bh=rPBCzzUJlptEP951D4yPK4MGsRf7+UEXKPZT7CVSj7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qqLCEJmA9IFBfR0P3qLvat1ficKMn4sJRXUCFDcRnXyTvvCZu74JvV2eMIeEbymDf Z/WJeuRzuE4Ys37ZeQN1mKg2BlNdyGGuXGn9/UASeZjUkqKtBuGerSl/aLYWb+ycj1 2AMYMPZsXvApBk16WkpV2v2Wb34wuzF09P4A3kAA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728819AbfE3DvI (ORCPT ); Wed, 29 May 2019 23:51:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:56600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732033AbfE3DTs (ORCPT ); Wed, 29 May 2019 23:19:48 -0400 Received: from localhost (ip67-88-213-2.z213-88-67.customer.algx.net [67.88.213.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 32CDF248D3; Thu, 30 May 2019 03:19:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559186388; bh=rPBCzzUJlptEP951D4yPK4MGsRf7+UEXKPZT7CVSj7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fxrq9Kzx4m8meooccA4mQomjD4B2kc+xRrKEb9NlkZqpLIdck5sGqvVXyRzBxx5DA 448djDsaIZvytFdPyhhcpwwwkOAJkyB5O+WqdCdxDZJeEbtaGtXwl05vvepX7hRMKk 7zAvQmqw0tHHcfXwgeBqoEdn5cLNm3GUOZwUueB4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Christian=20K=C3=B6nig?= , Chunming Zhou , Alex Deucher , Sasha Levin Subject: [PATCH 4.14 122/193] drm/amdgpu: fix old fence check in amdgpu_fence_emit Date: Wed, 29 May 2019 20:06:16 -0700 Message-Id: <20190530030505.578069191@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030446.953835040@linuxfoundation.org> References: <20190530030446.953835040@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 3d2aca8c8620346abdba96c6300d2c0b90a1d0cc ] We don't hold a reference to the old fence, so it can go away any time we are waiting for it to signal. Signed-off-by: Christian König Reviewed-by: Chunming Zhou Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 24 ++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c index 333bad7490678..415e9a384799e 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c @@ -135,8 +135,9 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f) { struct amdgpu_device *adev = ring->adev; struct amdgpu_fence *fence; - struct dma_fence *old, **ptr; + struct dma_fence __rcu **ptr; uint32_t seq; + int r; fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_KERNEL); if (fence == NULL) @@ -152,15 +153,24 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f) seq, AMDGPU_FENCE_FLAG_INT); ptr = &ring->fence_drv.fences[seq & ring->fence_drv.num_fences_mask]; + if (unlikely(rcu_dereference_protected(*ptr, 1))) { + struct dma_fence *old; + + rcu_read_lock(); + old = dma_fence_get_rcu_safe(ptr); + rcu_read_unlock(); + + if (old) { + r = dma_fence_wait(old, false); + dma_fence_put(old); + if (r) + return r; + } + } + /* This function can't be called concurrently anyway, otherwise * emitting the fence would mess up the hardware ring buffer. */ - old = rcu_dereference_protected(*ptr, 1); - if (old && !dma_fence_is_signaled(old)) { - DRM_INFO("rcu slot is busy\n"); - dma_fence_wait(old, false); - } - rcu_assign_pointer(*ptr, dma_fence_get(&fence->base)); *f = &fence->base; -- 2.20.1