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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 87157C3A5A9 for ; Wed, 4 Sep 2019 20:29:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5673921883 for ; Wed, 4 Sep 2019 20:29:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=poorly.run header.i=@poorly.run header.b="LV1epChq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727125AbfIDU3k (ORCPT ); Wed, 4 Sep 2019 16:29:40 -0400 Received: from mail-yw1-f66.google.com ([209.85.161.66]:46709 "EHLO mail-yw1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726495AbfIDU3k (ORCPT ); Wed, 4 Sep 2019 16:29:40 -0400 Received: by mail-yw1-f66.google.com with SMTP id 201so7753569ywo.13 for ; Wed, 04 Sep 2019 13:29:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=poorly.run; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8GtbizlkMPrZXUURKhwXVzGIR9K6zwzCUzTAta15LT4=; b=LV1epChq+XeeoVIIhc5b8513dZ1Zaf5mhdGuMY6vqmzkhclsDa1eGolRtdkXM05Aor w27i24ss9e34HGiNmSXw9xlXVWFa7L7bS55caQXhF5SNwIW4bigdsPmUmi5ZszvwtQhp 2DclMTptrrcpuzJPkjqnWOLwZmyQ80dlQYlImQFvFGdAol6unqCvrwteSpvTrjOS84k9 HpVoUr+OnIUpIkpUvmMYDBTkxWCaxOirHuVTISnl26naDe9SPyYJDD7Rv1DhrdzErEQG pQc6wBcNy+/NokXcc6+ftNYqeoI1IKfdq6/V0nR5/l+IQHzvLx/dIPIc2rQfLl0kkppk 6HmQ== 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:mime-version :content-transfer-encoding; bh=8GtbizlkMPrZXUURKhwXVzGIR9K6zwzCUzTAta15LT4=; b=eHdfPSsDK1trOKi4ghhgb9jHccs/ey3yYMGydhOgpwXUhmBVh+AsXNg/cg53kbXWq8 O2LBoKpBPag09p4yMXBMHZc52zinGQdaEZcvRlDlhy/qIrnACVe6eZm6c7cDVjkFfJx+ xEBQ2OM2pLYDjCkmGBSJxbJD8FYsEEUOPPn772VyTYci5YLvcJs+g6BZXLJZZkZIwnhi +c2napGjI6cAhw0vqx1el+Rq9GD1Hsh5gmtgqV45cwx+xRIHpHd6rw6l7+SB+RQriQLs bAi1YaIzRQxxjmgVyU+hvw8O1HMdexb2njSfmDn6+3sJkTcBQYnRkpUYmt9Gpcpk5poa GsYw== X-Gm-Message-State: APjAAAVDjfpQVzgt9QbmVqny8E8vCvz5DNrPA+Hy5iqQgfu7g11zAZik lZTIHv3f6hELyCL/yeG/kmUWaQ== X-Google-Smtp-Source: APXvYqzVzAqe0E9A0gTrZGdq7KqWNEa/VHDLOQmWN98uN10FARcUPQTpZMY9ST8qYTYl/d2DXXAApw== X-Received: by 2002:a81:7046:: with SMTP id l67mr7393356ywc.253.1567628979608; Wed, 04 Sep 2019 13:29:39 -0700 (PDT) Received: from rosewood.cam.corp.google.com ([2620:0:1013:11:89c6:2139:5435:371d]) by smtp.gmail.com with ESMTPSA id z137sm1944393ywd.18.2019.09.04.13.29.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Sep 2019 13:29:39 -0700 (PDT) From: Sean Paul To: dri-devel@lists.freedesktop.org Cc: Sean Paul , Rob Clark , Deepak Rawat , Daniel Vetter , Thomas Hellstrom , Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , Daniel Vetter , stable@vger.kernel.org Subject: [PATCH] drm: damage_helper: Fix race checking plane->state->fb Date: Wed, 4 Sep 2019 16:29:13 -0400 Message-Id: <20190904202938.110207-1-sean@poorly.run> X-Mailer: git-send-email 2.23.0.187.g17f5b7556c-goog 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: Sean Paul Since the dirtyfb ioctl doesn't give us any hints as to which plane is scanning out the fb it's marking as damaged, we need to loop through planes to find it. Currently we just reach into plane state and check, but that can race with another commit changing the fb out from under us. This patch locks the plane before checking the fb and will release the lock if the plane is not displaying the dirty fb. Fixes: b9fc5e01d1ce ("drm: Add helper to implement legacy dirtyfb") Cc: Rob Clark Cc: Deepak Rawat Cc: Daniel Vetter Cc: Thomas Hellstrom Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Sean Paul Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Cc: # v5.0+ Reported-by: Daniel Vetter Signed-off-by: Sean Paul --- drivers/gpu/drm/drm_damage_helper.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c index 8230dac01a89..3a4126dc2520 100644 --- a/drivers/gpu/drm/drm_damage_helper.c +++ b/drivers/gpu/drm/drm_damage_helper.c @@ -212,8 +212,14 @@ int drm_atomic_helper_dirtyfb(struct drm_framebuffer *fb, drm_for_each_plane(plane, fb->dev) { struct drm_plane_state *plane_state; - if (plane->state->fb != fb) + ret = drm_modeset_lock(&plane->mutex, state->acquire_ctx); + if (ret) + goto out; + + if (plane->state->fb != fb) { + drm_modeset_unlock(&plane->mutex); continue; + } plane_state = drm_atomic_get_plane_state(state, plane); if (IS_ERR(plane_state)) { -- Sean Paul, Software Engineer, Google / Chromium OS