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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 D0EA5C2BA16 for ; Tue, 7 Apr 2020 06:26:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A3EA520730 for ; Tue, 7 Apr 2020 06:26:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MZIdjAh2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727049AbgDGG0z (ORCPT ); Tue, 7 Apr 2020 02:26:55 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:37262 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726030AbgDGG0z (ORCPT ); Tue, 7 Apr 2020 02:26:55 -0400 Received: by mail-pf1-f193.google.com with SMTP id u65so333600pfb.4 for ; Mon, 06 Apr 2020 23:26:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=jy977meOP1x2g1uwfOo8VvxcnJENx8VXf+a5CPnPB0Y=; b=MZIdjAh2Ez1wofKZ+wn7aL/BWxBmauimXI6PRuJC1wV41Pype8abxbRAKRBfYlA9SF YHFrCNT7SO8xuqpwrEZEjxmgp8MQrkvLe7ple9w6bij6CUE4z4yv2G0u04mbdx9VPncb VLyeLjUjxBhtMkxxmm2JUwKCqTzVo9WT/oc5GLTzDXAW9fosw0giH/52NDqWXuhsmmFi E/Jp6/VymRPhe8BpSmy2r/yXB1vBnyMIKqfCDXzhqU2Yxh+/iPHgelcU2SB7ff4N8ivx DQ1ve9DdBdIPhAFqRYvqJozJMszZOzq6TbNICy9V7a75FHQ1Knt6C+qeY7diaUF9AfuY gbgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=jy977meOP1x2g1uwfOo8VvxcnJENx8VXf+a5CPnPB0Y=; b=nZL4OQGKmQHzAwH3WOD6JXW+kGCQPF9QZIpobf078/3ZVCLAutxwpbKG5GXtgEVH5p j7hotFst0xIc8wz+DBW+Gn1POstq54DjEN4Wr7I2G19icOLI70kIFkvIo30crPm13NkY ZU7NhHjpZdtd+dfBnn/dMa9zAuRUR8VNOc9otCM+RPqEYGjCxmdA4eCYgDDNV1FquXbj ZAgXxde83/I1RcwnkdZasVBqsnXWAQz7RMudXgIWbXY3sXGpXw7f5IJLc31FqbVF+iFu 041+lCa9wP+cDvXEeXtTRS/l5qvd8nodijMIo6AB0JgHZlDmngiGoyGqZIQMUYdBJldX PFiA== X-Gm-Message-State: AGi0PuZByWF8jkDIZy4keR3/RMlJQAJelgxLe+bAN4orMlAoKOO9glkV HmFlgc1nl0bd2dDEWxOaRBsg7vHd X-Google-Smtp-Source: APiQypIilbINLPrUGoKy7ywgHGom36AC24wZuq/hJ3V4bFgUTJoRJ1cFGpR+3vP9+2DVN6t9y8vLYg== X-Received: by 2002:a63:a51e:: with SMTP id n30mr552785pgf.414.1586240813483; Mon, 06 Apr 2020 23:26:53 -0700 (PDT) Received: from sultan-box.localdomain (static-198-54-129-52.cust.tzulo.com. [198.54.129.52]) by smtp.gmail.com with ESMTPSA id y9sm13554620pfo.135.2020.04.06.23.26.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Apr 2020 23:26:52 -0700 (PDT) From: Sultan Alsawaf X-Google-Original-From: Sultan Alsawaf To: stable@vger.kernel.org Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , Chris Wilson , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Sultan Alsawaf Subject: [PATCH 0/1] drm/i915: Fix a deadlock that only affects 5.4 Date: Mon, 6 Apr 2020 23:26:21 -0700 Message-Id: <20200407062622.6443-1-sultan@kerneltoast.com> X-Mailer: git-send-email 2.26.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sultan Alsawaf Hi, There's a mutex lock deadlock in i915 that only affects 5.4, but was fixed in 5.5. Normally, I would send a backport of the fix from 5.5, but the patch set that fixes the deadlock involves massive changes that are neither feasible nor desirable for backporting [1][2][3]. Therefore, I've made a small patch that only addresses the deadlock specifically for 5.4. Thanks, Sultan [1] 274cbf20fd10 ("drm/i915: Push the i915_active.retire into a worker") [2] 093b92287363 ("drm/i915: Split i915_active.mutex into an irq-safe spinlock for the rbtree") [3] 750bde2fd4ff ("drm/i915: Serialise with remote retirement") Sultan Alsawaf (1): drm/i915: Fix ref->mutex deadlock in i915_active_wait() drivers/gpu/drm/i915/i915_active.c | 27 +++++++++++++++++++++++---- drivers/gpu/drm/i915/i915_active.h | 4 ++-- 2 files changed, 25 insertions(+), 6 deletions(-) -- 2.26.0