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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 E38ABC4338F for ; Tue, 24 Aug 2021 15:47:54 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A3F4160725 for ; Tue, 24 Aug 2021 15:47:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A3F4160725 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 27AD389A88; Tue, 24 Aug 2021 15:47:54 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0FF9A89A88; Tue, 24 Aug 2021 15:47:52 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10086"; a="217343213" X-IronPort-AV: E=Sophos;i="5.84,347,1620716400"; d="scan'208";a="217343213" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 08:47:52 -0700 X-IronPort-AV: E=Sophos;i="5.84,347,1620716400"; d="scan'208";a="425509683" Received: from jons-linux-dev-box.fm.intel.com (HELO jons-linux-dev-box) ([10.1.27.20]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 08:47:52 -0700 Date: Tue, 24 Aug 2021 08:42:41 -0700 From: Matthew Brost To: Daniele Ceraolo Spurio Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, daniel.vetter@ffwll.ch Message-ID: <20210824154241.GA9672@jons-linux-dev-box> References: <20210819061639.21051-1-matthew.brost@intel.com> <20210819061639.21051-14-matthew.brost@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Subject: Re: [Intel-gfx] [PATCH 13/27] drm/i915/guc: Take context ref when cancelling request X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Fri, Aug 20, 2021 at 05:07:27PM -0700, Daniele Ceraolo Spurio wrote: > > > On 8/18/2021 11:16 PM, Matthew Brost wrote: > > A context can get destroyed after cancelling a request so take a > > reference to context when cancelling a request. > > What's the exact race? AFAICS __i915_request_skip does not have a > context_put(). This commit message isn't quite right, it is really a context reset or a GT reset which could result in the context getting destroyed. I haven't actually seen this happen but this just being paranoid about ref counting. Can fix up the commit message. Matt > > Daniele > > > > > Fixes: 62eaf0ae217d ("drm/i915/guc: Support request cancellation") > > Signed-off-by: Matthew Brost > > --- > > drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > index e0e85e4ad512..85f96d325048 100644 > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > > @@ -1620,8 +1620,10 @@ static void guc_context_cancel_request(struct intel_context *ce, > > struct i915_request *rq) > > { > > if (i915_sw_fence_signaled(&rq->submit)) { > > - struct i915_sw_fence *fence = guc_context_block(ce); > > + struct i915_sw_fence *fence; > > + intel_context_get(ce); > > + fence = guc_context_block(ce); > > i915_sw_fence_wait(fence); > > if (!i915_request_completed(rq)) { > > __i915_request_skip(rq); > > @@ -1636,6 +1638,7 @@ static void guc_context_cancel_request(struct intel_context *ce, > > flush_work(&ce_to_guc(ce)->ct.requests.worker); > > guc_context_unblock(ce); > > + intel_context_put(ce); > > } > > } >