From patchwork Fri Aug 6 08:16:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 493303 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 2F4A4C432BE for ; Fri, 6 Aug 2021 08:21:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E21B61206 for ; Fri, 6 Aug 2021 08:21:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244379AbhHFIVn (ORCPT ); Fri, 6 Aug 2021 04:21:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:52360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244255AbhHFIUd (ORCPT ); Fri, 6 Aug 2021 04:20:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 98D7A61206; Fri, 6 Aug 2021 08:20:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1628238016; bh=vV1kBFJSLi3yOLCobttpep3V2bs02zHCnpF5GWEKdV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fp7fbE7EjzqU6/lTfutHsnVlSNrExeOSE8lTphb8M2N5lsRvUqT+LdhLZSXuUGkbN Rom6mYCXoXiuBfxaobNZ2KT8WjWn6nBtxDLigdJ1XxWfiYcxbNMPJrgq9yOMmmIHXB Pb3pbp2+ctxwDJIVyNIuCz2E9zHLauMlX6vZL2wo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Ekstrand , Marcin Slusarz , Jason Ekstrand , Daniel Vetter , Jon Bloomfield , Rodrigo Vivi , Sasha Levin Subject: [PATCH 5.13 02/35] Revert "drm/i915: Propagate errors on awaiting already signaled fences" Date: Fri, 6 Aug 2021 10:16:45 +0200 Message-Id: <20210806081113.796798036@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210806081113.718626745@linuxfoundation.org> References: <20210806081113.718626745@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jason Ekstrand commit 3761baae908a7b5012be08d70fa553cc2eb82305 upstream. This reverts commit 9e31c1fe45d555a948ff66f1f0e3fe1f83ca63f7. Ever since that commit, we've been having issues where a hang in one client can propagate to another. In particular, a hang in an app can propagate to the X server which causes the whole desktop to lock up. Error propagation along fences sound like a good idea, but as your bug shows, surprising consequences, since propagating errors across security boundaries is not a good thing. What we do have is track the hangs on the ctx, and report information to userspace using RESET_STATS. That's how arb_robustness works. Also, if my understanding is still correct, the EIO from execbuf is when your context is banned (because not recoverable or too many hangs). And in all these cases it's up to userspace to figure out what is all impacted and should be reported to the application, that's not on the kernel to guess and automatically propagate. What's more, we're also building more features on top of ctx error reporting with RESET_STATS ioctl: Encrypted buffers use the same, and the userspace fence wait also relies on that mechanism. So it is the path going forward for reporting gpu hangs and resets to userspace. So all together that's why I think we should just bury this idea again as not quite the direction we want to go to, hence why I think the revert is the right option here. For backporters: Please note that you _must_ have a backport of https://lore.kernel.org/dri-devel/20210602164149.391653-2-jason@jlekstrand.net/ for otherwise backporting just this patch opens up a security bug. v2: Augment commit message. Also restore Jason's sob that I accidentally lost. v3: Add a note for backporters Signed-off-by: Jason Ekstrand Reported-by: Marcin Slusarz Cc: # v5.6+ Cc: Jason Ekstrand Cc: Marcin Slusarz Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3080 Fixes: 9e31c1fe45d5 ("drm/i915: Propagate errors on awaiting already signaled fences") Acked-by: Daniel Vetter Reviewed-by: Jon Bloomfield Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210714193419.1459723-3-jason@jlekstrand.net (cherry picked from commit 93a2711cddd5760e2f0f901817d71c93183c3b87) Signed-off-by: Rodrigo Vivi Signed-off-by: Sasha Levin --- drivers/gpu/drm/i915/i915_request.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index bec9c3652188..59d48a6a83d2 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -1426,10 +1426,8 @@ i915_request_await_execution(struct i915_request *rq, do { fence = *child++; - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) { - i915_sw_fence_set_error_once(&rq->submit, fence->error); + if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) continue; - } if (fence->context == rq->fence.context) continue; @@ -1527,10 +1525,8 @@ i915_request_await_dma_fence(struct i915_request *rq, struct dma_fence *fence) do { fence = *child++; - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) { - i915_sw_fence_set_error_once(&rq->submit, fence->error); + if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) continue; - } /* * Requests on the same timeline are explicitly ordered, along