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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54F90C433F5 for ; Wed, 4 May 2022 15:21:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352412AbiEDPYq (ORCPT ); Wed, 4 May 2022 11:24:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352360AbiEDPYe (ORCPT ); Wed, 4 May 2022 11:24:34 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2823443CD for ; Wed, 4 May 2022 08:20:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651677640; x=1683213640; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=dJIYLg7h/Q2ldxRvg4MeqMb9Yi/SXMhu0fJoO84kF6w=; b=lTt1SOXV97GnZsD3Dkp5l1radovx1owFuprhEg/0OAjCazsO9ZrJibrj 116Pho5E4M4lev9x1i/9XuHKvU5A5hSDATm5sEH73NR+Ic0jo21aOaLoP SKkysd+EgaKC0itblpwnSsFDfgCxVgaTqIZQWDZCYGLv3dBnOPeyi332r 4J9GS47H1wTV6p6FoIFSjGxNd53Sw2oWzb2Cs45e2SmSaNmyvRgWH+tYw cjJWAs4+wSOkGl/RORIeOMQWt0UBdldM1DsMP3su+Nnc+7JBIeTBI7Yr5 c6gV0rRJzsZNpYd8VPoiLg/snlGxK3aACcIxrtvCHHEO9reRi9tDMFF8V Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10337"; a="255263050" X-IronPort-AV: E=Sophos;i="5.91,198,1647327600"; d="scan'208";a="255263050" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2022 08:20:40 -0700 X-IronPort-AV: E=Sophos;i="5.91,198,1647327600"; d="scan'208";a="664511899" Received: from gidaly-mobl1.ger.corp.intel.com (HELO [10.213.236.183]) ([10.213.236.183]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2022 08:20:38 -0700 Message-ID: <1ff8137a-7ae6-5162-525d-70373a7170db@linux.intel.com> Date: Wed, 4 May 2022 16:20:37 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [Intel-gfx] [PATCH v2] drm/i915: Fix race in __i915_vma_remove_closed Content-Language: en-US To: Karol Herbst , linux-kernel@vger.kernel.org Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Chris Wilson References: <20220420095720.3331609-1-kherbst@redhat.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc In-Reply-To: <20220420095720.3331609-1-kherbst@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/04/2022 10:57, Karol Herbst wrote: > i915_vma_reopen checked if the vma is closed before without taking the > lock. So multiple threads could attempt removing the vma. > > Instead the lock needs to be taken before actually checking. > > v2: move struct declaration > > Cc: Chris Wilson > Cc: intel-gfx@lists.freedesktop.org > Cc: dri-devel@lists.freedesktop.org > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5732 > Signed-off-by: Karol Herbst Reviewed-by: Tvrtko Ursulin Regards, Tvrtko > --- > drivers/gpu/drm/i915/i915_vma.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c > index 162e8d83691b..2efdad2b43fa 100644 > --- a/drivers/gpu/drm/i915/i915_vma.c > +++ b/drivers/gpu/drm/i915/i915_vma.c > @@ -1615,17 +1615,17 @@ void i915_vma_close(struct i915_vma *vma) > > static void __i915_vma_remove_closed(struct i915_vma *vma) > { > - struct intel_gt *gt = vma->vm->gt; > - > - spin_lock_irq(>->closed_lock); > list_del_init(&vma->closed_link); > - spin_unlock_irq(>->closed_lock); > } > > void i915_vma_reopen(struct i915_vma *vma) > { > + struct intel_gt *gt = vma->vm->gt; > + > + spin_lock_irq(>->closed_lock); > if (i915_vma_is_closed(vma)) > __i915_vma_remove_closed(vma); > + spin_unlock_irq(>->closed_lock); > } > > static void force_unbind(struct i915_vma *vma) > @@ -1641,6 +1641,7 @@ static void force_unbind(struct i915_vma *vma) > static void release_references(struct i915_vma *vma, bool vm_ddestroy) > { > struct drm_i915_gem_object *obj = vma->obj; > + struct intel_gt *gt = vma->vm->gt; > > GEM_BUG_ON(i915_vma_is_active(vma)); > > @@ -1651,7 +1652,9 @@ static void release_references(struct i915_vma *vma, bool vm_ddestroy) > > spin_unlock(&obj->vma.lock); > > + spin_lock_irq(>->closed_lock); > __i915_vma_remove_closed(vma); > + spin_unlock_irq(>->closed_lock); > > if (vm_ddestroy) > i915_vm_resv_put(vma->vm);