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 13025C83F3E for ; Mon, 4 Sep 2023 00:49:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350000AbjIDAti (ORCPT ); Sun, 3 Sep 2023 20:49:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349873AbjIDAth (ORCPT ); Sun, 3 Sep 2023 20:49:37 -0400 X-Greylist: delayed 471 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Sun, 03 Sep 2023 17:49:33 PDT Received: from james.steelbluetech.co.uk (james.steelbluetech.co.uk [92.63.139.228]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CF1FFB; Sun, 3 Sep 2023 17:49:33 -0700 (PDT) Received: from [10.0.5.25] (tv.ehuk.net [10.0.5.25]) by james.steelbluetech.co.uk (Postfix) with ESMTP id A3C05BFC11; Mon, 4 Sep 2023 01:41:38 +0100 (BST) DKIM-Filter: OpenDKIM Filter v2.10.3 james.steelbluetech.co.uk A3C05BFC11 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ehuk.net; s=default; t=1693788098; bh=QVu39wB/wdpDUmhFZ16BD56J1JZefShVT6nfmmsX3aU=; h=Date:Reply-To:Subject:To:Cc:References:From:In-Reply-To:From; b=r/tLnuN0s51iXJIk2yGflAPpi8cBtPKDfxH2ixJ+IMzo/2qGEOB93wugoMCqqWKWn +T4ObAGsDKuoC1O/uz2i1YI/e4yqkl9weiCOMfZ4mXRLMZAHi+njmG7kt4qHUjllBZ /hgI22tb0T+r6U6uGrPXC2Lw8al3k5OdkhPDNjre7Vh8RHwNSjOh7iRwatQyGJPexJ QIcKl5TFFt3mjLTsSJH6BbUI/7/WbcK0WHtByW4iiYO6c+WSzSIZJ0CcXOA/MSOgyo JgtuSEFyYnH0lXJM5mAUjUipe4d3YNGtV1RYfISXJiOWVXPgb/kWDjNIC9Aq9sA0s7 ujcxwi3BVRb+w== Message-ID: Date: Mon, 4 Sep 2023 01:41:38 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Reply-To: eddie@ehuk.net Subject: Re: [PATCH AUTOSEL 5.10 13/22] drm/amdgpu: install stub fence into potential unused fence pointers To: =?UTF-8?Q?Christian_K=c3=b6nig?= , Chia-I Wu , Greg KH Cc: Sasha Levin , airlied@linux.ie, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, Alex Deucher , stable@vger.kernel.org, Lang Yu , =?UTF-8?Q?Christian_K=c3=b6nig?= References: <20230724012419.2317649-1-sashal@kernel.org> <20230724012419.2317649-13-sashal@kernel.org> <55fc4a28-1e17-44df-2069-a688828080e6@gmail.com> <2023083145-scoured-celery-2511@gregkh> <2023083144-railroad-daybreak-7f41@gregkh> <44fd45f9-8e2c-f9a2-fe89-97329734e13c@gmail.com> Content-Language: en-GB From: Eddie Chapman In-Reply-To: <44fd45f9-8e2c-f9a2-fe89-97329734e13c@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/09/2023 07:02, Christian König wrote: > Am 31.08.23 um 20:55 schrieb Chia-I Wu: >> On Thu, Aug 31, 2023 at 7:01 AM Greg KH >> wrote: >>> On Thu, Aug 31, 2023 at 03:26:28PM +0200, Christian König wrote: >>>> Am 31.08.23 um 12:56 schrieb Greg KH: >>>>> On Thu, Aug 31, 2023 at 12:27:27PM +0200, Christian König wrote: >>>>>> Am 30.08.23 um 20:53 schrieb Chia-I Wu: >>>>>>> On Sun, Jul 23, 2023 at 6:24 PM Sasha Levin >>>>>>> wrote: >>>>>>>> From: Lang Yu >>>>>>>> >>>>>>>> [ Upstream commit 187916e6ed9d0c3b3abc27429f7a5f8c936bd1f0 ] >>>>>>>> >>>>>>>> When using cpu to update page tables, vm update fences are unused. >>>>>>>> Install stub fence into these fence pointers instead of NULL >>>>>>>> to avoid NULL dereference when calling dma_fence_wait() on them. >>>>>>>> >>>>>>>> Suggested-by: Christian König >>>>>>>> Signed-off-by: Lang Yu >>>>>>>> Reviewed-by: Christian König >>>>>>>> Signed-off-by: Alex Deucher >>>>>>>> Signed-off-by: Sasha Levin >>>>>>>> --- >>>>>>>>     drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 6 ++++-- >>>>>>>>     1 file changed, 4 insertions(+), 2 deletions(-) >>>>>>> We start getting this warning spew on chromeos >>>>>> Yeah because the older kernels still kept track of the last VM >>>>>> fence in the >>>>>> syncobj. >>>>>> >>>>>> This patch here should probably not have been back ported. >>>>>> >>>>>> Why was that done anyway? The upstream commit doesn't have a CC >>>>>> stable and >>>>>> this is only a bug fix for a new feature not present on older >>>>>> kernels. >>>>> It is part of the AUTOSEL process. >>>> Could we prevent patches from being backported by adding a Fixes: tag? >>> Yes, that will show exactly where the patch should be backported to. >> This is also AUTOSEL'ed to 5.15.  That might need a revert as well, >> depending on when the amdgpu feature landed. > > Both the feature and the bug fix landed in 6.5. > > The bug fix should have never been backported to any older kernel at all > as far as I can see. > > Regards, > Christian. I can confirm I've also started to get this warning hundreds of times per second having upgraded from 5.15.123 to 5.15.130. There's also a report from someone else of exactly the same on 5.15.128, here: https://gitlab.freedesktop.org/drm/amd/-/issues/2820 Eddie