From patchwork Wed Jul 14 19:34:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Ekstrand X-Patchwork-Id: 12377761 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 AFAE6C47E4B for ; Wed, 14 Jul 2021 19:34:38 +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 7786061370 for ; Wed, 14 Jul 2021 19:34:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7786061370 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=jlekstrand.net 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 02FC86E4DD; Wed, 14 Jul 2021 19:34:33 +0000 (UTC) Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by gabe.freedesktop.org (Postfix) with ESMTPS id C15C16E4D4 for ; Wed, 14 Jul 2021 19:34:30 +0000 (UTC) Received: by mail-pf1-x42a.google.com with SMTP id m83so2982129pfd.0 for ; Wed, 14 Jul 2021 12:34:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jlekstrand-net.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=8g0NKGsiBt+LRz/CeZwrcLpTtaHucndBMGpot3ZHzBo=; b=yWsa9uBzT4hk3NcPhCG3JMvB3gAraFy3dbpmKYJ7o2evC99NZ2FkBYCuyUtIccEDGY bJBcOAANtWB6TKchz4y6lQQowmPryZgDeemTRiRb0qrE6XLyQ2iiMjrEeaFlVi4fPrzC TVnGqSR/dxU4Gx2pIzXx35aZfJ1BV4Er+ZPhp0M/SiIODQ6p9bUgBCQQ/5Da4m6qyaOz VJy55WvmGBER1bZgBquV3a7oBcryf+vFGD84KTqRUPtDPxfjJYphYA8rfh/OKfX6Pt+c 2U+osrKydcI7MUh1YdkGT4ewAEf0Za4BPVQuGHAE7p57AOKGyOND2daEGgByavX2mfsV kJ/A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=8g0NKGsiBt+LRz/CeZwrcLpTtaHucndBMGpot3ZHzBo=; b=pl2DZru5LRk2C+I577T4tJEYbW7daGXWchz0luVAZQ1ixJk7JAyw0z294HF5DkdOav Tu3Xv1TSUurVUG479PMTqjSsH/SahxJBb0uuyZCYZn9MQlqhhsGScjh0yZxiubzQjjd4 be985CZr33HhD0Rjle8h1ujJryfSBmQJaajsAeie+jkRnQ0n+35sZW4YUiWsU0BvXgDN T9kQolLWcoyDqIO5vgktI8ZC/IoDF5IlY2DLc5zyeAqNmjjrZp1Z2oiUcYxmu/NV2RMx ygffRImxWc6mz9Y4i7IueKVv5c1musNGqCjtn2KeJo/qB0LJXs4MsUsuw4MWwcjY2PrM MKlg== X-Gm-Message-State: AOAM532egP7/a67nrZbNpUi3cApnS1cnMzbnO1y/UvsgFHMnVBhRbaFd 46Z34x/8xYGdA9Lh95gh76atSwujwOOrMw== X-Google-Smtp-Source: ABdhPJx2Kt5tejKPEix4ne/J6ilOQy1+0CAgqPl4xeuT5GntMfxp+J9m9dr4TElop+/9eSQ036pN9Q== X-Received: by 2002:a63:d711:: with SMTP id d17mr11137949pgg.268.1626291270299; Wed, 14 Jul 2021 12:34:30 -0700 (PDT) Received: from omlet.com ([134.134.139.71]) by smtp.gmail.com with ESMTPSA id i1sm3679740pfo.37.2021.07.14.12.34.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Jul 2021 12:34:29 -0700 (PDT) From: Jason Ekstrand To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Date: Wed, 14 Jul 2021 14:34:16 -0500 Message-Id: <20210714193419.1459723-3-jason@jlekstrand.net> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210714193419.1459723-1-jason@jlekstrand.net> References: <20210714193419.1459723-1-jason@jlekstrand.net> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 2/5] Revert "drm/i915: Propagate errors on awaiting already signaled fences" 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: Daniel Vetter , stable@vger.kernel.org, Jason Ekstrand Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" 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 --- 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 86b4c9f2613d5..09ebea9a0090a 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -1399,10 +1399,8 @@ 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; @@ -1499,10 +1497,8 @@ 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