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: 12377803 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 F3B13C1B08C for ; Wed, 14 Jul 2021 19:34:36 +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 BF8C7613BA for ; Wed, 14 Jul 2021 19:34:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF8C7613BA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=jlekstrand.net 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 8F22A6E4D4; Wed, 14 Jul 2021 19:34:32 +0000 (UTC) Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by gabe.freedesktop.org (Postfix) with ESMTPS id 968886E4D4 for ; Wed, 14 Jul 2021 19:34:30 +0000 (UTC) Received: by mail-pf1-x432.google.com with SMTP id p36so2924990pfw.11 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=bBksGPu+jNfWC6Q1bBclyQNo8suw+JMjWjYUz60oEE9ao+5YIqnu74PQ0Ww7smzWOq dLZWa8NAyc4VcG3q9Ke8aujwrPQz6WcUJ2WxmMTBcWvYnvMPJEhZjPvSyxNd0kQiVSJX oOXDwrWPujnvMYkHRu2XcVcrKqkY6S1LrfJIm2Pm6uRZm48RnlKGn/Zqr93n63+XrYFq jFh/EnMTrknv26nxj8/3cK1xcVyznimYvsS9/J8BFaAfkd4EwgNc0OpfMlTTRpaTX16e 8Hy39JJ6ywzzxDCIEXFaosz6ssKj213QmtHybUmfxWvONjz0wnhsUrw3rFPVGI/Llwif z7vg== X-Gm-Message-State: AOAM532qR79PtBEl8Nrwk/OfKrrgdhwgQf3/H3FVN1diNmxdPMSawpvS C9RBfO16x8Z/NENk/y9olR87pQ== 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 Subject: [PATCH 2/5] Revert "drm/i915: Propagate errors on awaiting already signaled fences" 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 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: Daniel Vetter , stable@vger.kernel.org, Jason Ekstrand , Jon Bloomfield , Jason Ekstrand , Marcin Slusarz Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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