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 E6628C433FE for ; Tue, 3 May 2022 09:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233504AbiECJlg (ORCPT ); Tue, 3 May 2022 05:41:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233520AbiECJlb (ORCPT ); Tue, 3 May 2022 05:41:31 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 578A536E30 for ; Tue, 3 May 2022 02:37:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1651570677; x=1683106677; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=JqAREk8vnvLu8bKhdmebDQaF1iMe+9wlfQ11DH7NkhU=; b=QAL2Ln5f4wKTkmwedtvaDbf+SSZqPP/zVMYy5W0B51XS9tiFu7ReKj/l Wm2qx0tWXdBJW/vB7fjjFZIlw2kM+Z9cxjmHc+F+e+dUqkeqN++vz9qBS E53P20vgkZ9pD7DjeLMIfDqhr+yBOeVl21ngocNYS6kVSqbqbBo6SMEOe oc3Y1lyXEn/lIqxNpLM/N+cz4W08D+pwhi3+Hm0HF0najbYL18cMR1cRp qXYkhL/Hre9duPfXZqLb6s05Ah6o3SU+TKKoqekG4rbykwdbv8h7qCzjo Mm4rbHQjvKAr62d05aAh0wikysFfAegT/T+ebMC/EK29ZEDpxripzn62e A==; X-IronPort-AV: E=McAfee;i="6400,9594,10335"; a="353878972" X-IronPort-AV: E=Sophos;i="5.91,194,1647327600"; d="scan'208";a="353878972" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 May 2022 02:36:59 -0700 X-IronPort-AV: E=Sophos;i="5.91,194,1647327600"; d="scan'208";a="562145028" Received: from doshaugh-mobl.ger.corp.intel.com (HELO [10.213.236.211]) ([10.213.236.211]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 May 2022 02:36:57 -0700 Message-ID: <4e3525db-5aa4-fec8-a496-749e08b5f257@linux.intel.com> Date: Tue, 3 May 2022 10:36:55 +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 Fix looks correct to me. In which case it seems breakage was introduced with: Fixes: 155ab8836caa ("drm/i915: Move object close under its own lock") Cc: Matthew Auld Cc: # v5.3+ AFAICT at least. I will add these tags and pull it in unless someone shouts a correction. Regards, Tvrtko > 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 > --- > 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);