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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 CDE66C2D0D2 for ; Wed, 18 Dec 2019 23:45:35 +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 AD8B2218AC for ; Wed, 18 Dec 2019 23:45:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD8B2218AC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9E4176EAA8; Wed, 18 Dec 2019 23:45:34 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1CEEF6EAA6; Wed, 18 Dec 2019 23:45:33 +0000 (UTC) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Dec 2019 15:45:32 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,330,1571727600"; d="scan'208";a="416004439" Received: from nvishwa1-desk.sc.intel.com ([10.3.160.185]) by fmsmga005.fm.intel.com with ESMTP; 18 Dec 2019 15:45:32 -0800 Date: Wed, 18 Dec 2019 15:34:23 -0800 From: Niranjana Vishwanathapura To: Jason Gunthorpe Subject: Re: [RFC v2 02/12] drm/i915/svm: Runtime (RT) allocator support Message-ID: <20191218233423.GE17413@nvishwa1-DESK.sc.intel.com> References: <20191213215614.24558-1-niranjana.vishwanathapura@intel.com> <20191213215614.24558-3-niranjana.vishwanathapura@intel.com> <20191217201815.GF16762@mellanox.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191217201815.GF16762@mellanox.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "kenneth.w.graunke@intel.com" , "intel-gfx@lists.freedesktop.org" , "sanjay.k.kumar@intel.com" , "sudeep.dutt@intel.com" , "dri-devel@lists.freedesktop.org" , "jason.ekstrand@intel.com" , "dave.hansen@intel.com" , "jglisse@redhat.com" , "jon.bloomfield@intel.com" , "daniel.vetter@intel.com" , "dan.j.williams@intel.com" , "ira.weiny@intel.com" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Dec 17, 2019 at 08:18:21PM +0000, Jason Gunthorpe wrote: >On Fri, Dec 13, 2019 at 01:56:04PM -0800, Niranjana Vishwanathapura wrote: > >> + ctx = i915_gem_context_lookup(file->driver_priv, args->rsvd1); >> + if (!ctx || !rcu_access_pointer(ctx->vm)) >> + return -ENOENT; >> + >> + rcu_read_lock(); >> + vm = i915_vm_get(ctx->vm); >> + rcu_read_unlock(); > >This looks like wrong use of RCU to me. > >Getting a rcu lock and not calling rcu_dereference under it is >basically guarenteed to be wrong.. > Oops, yah, I should be just calling i915_gem_context_get_vm_rcu(). Thanks, Niranjana >Jason _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 A8E0AC43603 for ; Wed, 18 Dec 2019 23:45:34 +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 82918218AC for ; Wed, 18 Dec 2019 23:45:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82918218AC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 00BBF6EAA6; Wed, 18 Dec 2019 23:45:34 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1CEEF6EAA6; Wed, 18 Dec 2019 23:45:33 +0000 (UTC) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Dec 2019 15:45:32 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,330,1571727600"; d="scan'208";a="416004439" Received: from nvishwa1-desk.sc.intel.com ([10.3.160.185]) by fmsmga005.fm.intel.com with ESMTP; 18 Dec 2019 15:45:32 -0800 Date: Wed, 18 Dec 2019 15:34:23 -0800 From: Niranjana Vishwanathapura To: Jason Gunthorpe Message-ID: <20191218233423.GE17413@nvishwa1-DESK.sc.intel.com> References: <20191213215614.24558-1-niranjana.vishwanathapura@intel.com> <20191213215614.24558-3-niranjana.vishwanathapura@intel.com> <20191217201815.GF16762@mellanox.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191217201815.GF16762@mellanox.com> User-Agent: Mutt/1.5.24 (2015-08-30) Subject: Re: [Intel-gfx] [RFC v2 02/12] drm/i915/svm: Runtime (RT) allocator support 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: , Cc: "kenneth.w.graunke@intel.com" , "intel-gfx@lists.freedesktop.org" , "sanjay.k.kumar@intel.com" , "dri-devel@lists.freedesktop.org" , "jason.ekstrand@intel.com" , "dave.hansen@intel.com" , "jglisse@redhat.com" , "daniel.vetter@intel.com" , "dan.j.williams@intel.com" , "ira.weiny@intel.com" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Dec 17, 2019 at 08:18:21PM +0000, Jason Gunthorpe wrote: >On Fri, Dec 13, 2019 at 01:56:04PM -0800, Niranjana Vishwanathapura wrote: > >> + ctx = i915_gem_context_lookup(file->driver_priv, args->rsvd1); >> + if (!ctx || !rcu_access_pointer(ctx->vm)) >> + return -ENOENT; >> + >> + rcu_read_lock(); >> + vm = i915_vm_get(ctx->vm); >> + rcu_read_unlock(); > >This looks like wrong use of RCU to me. > >Getting a rcu lock and not calling rcu_dereference under it is >basically guarenteed to be wrong.. > Oops, yah, I should be just calling i915_gem_context_get_vm_rcu(). Thanks, Niranjana >Jason _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx