From patchwork Wed Oct 13 16:13:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kai Vehmanen X-Patchwork-Id: 12556337 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6457EC433FE for ; Wed, 13 Oct 2021 16:24:19 +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 0070660551 for ; Wed, 13 Oct 2021 16:24:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0070660551 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 06AE96EA89; Wed, 13 Oct 2021 16:24:18 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2490B6EA78; Wed, 13 Oct 2021 16:24:16 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10136"; a="250892451" X-IronPort-AV: E=Sophos;i="5.85,371,1624345200"; d="scan'208";a="250892451" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2021 09:20:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.85,371,1624345200"; d="scan'208";a="659594214" Received: from eliteleevi.tm.intel.com ([10.237.54.20]) by orsmga005.jf.intel.com with ESMTP; 13 Oct 2021 09:20:44 -0700 From: Kai Vehmanen To: dri-devel@lists.freedesktop.org, gregkh@linuxfoundation.org, tiwai@suse.de Cc: alsa-devel@alsa-project.org, jani.nikula@intel.com, Imre Deak , Russell King , "Rafael J . Wysocki" , kai.vehmanen@linux.intel.com, intel-gfx@lists.freedesktop.org, stable@vger.kernel.org, Russell King Subject: [PATCH v3] component: do not leave master devres group open after bind Date: Wed, 13 Oct 2021 19:13:45 +0300 Message-Id: <20211013161345.3755341-1-kai.vehmanen@linux.intel.com> X-Mailer: git-send-email 2.33.0 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" In current code, the devres group for aggregate master is left open after call to component_master_add_*(). This leads to problems when the master does further managed allocations on its own. When any participating driver calls component_del(), this leads to immediate release of resources. This came up when investigating a page fault occurring with i915 DRM driver unbind with 5.15-rc1 kernel. The following sequence occurs: i915_pci_remove() -> intel_display_driver_unregister() -> i915_audio_component_cleanup() -> component_del() -> component.c:take_down_master() -> hdac_component_master_unbind() [via master->ops->unbind()] -> devres_release_group(master->parent, NULL) With older kernels this has not caused issues, but with audio driver moving to use managed interfaces for more of its allocations, this no longer works. Devres log shows following to occur: component_master_add_with_match() [ 126.886032] snd_hda_intel 0000:00:1f.3: DEVRES ADD 00000000323ccdc5 devm_component_match_release (24 bytes) [ 126.886045] snd_hda_intel 0000:00:1f.3: DEVRES ADD 00000000865cdb29 grp< (0 bytes) [ 126.886049] snd_hda_intel 0000:00:1f.3: DEVRES ADD 000000001b480725 grp< (0 bytes) audio driver completes its PCI probe() [ 126.892238] snd_hda_intel 0000:00:1f.3: DEVRES ADD 000000001b480725 pcim_iomap_release (48 bytes) component_del() called() at DRM/i915 unbind() [ 137.579422] i915 0000:00:02.0: DEVRES REL 00000000ef44c293 grp< (0 bytes) [ 137.579445] snd_hda_intel 0000:00:1f.3: DEVRES REL 00000000865cdb29 grp< (0 bytes) [ 137.579458] snd_hda_intel 0000:00:1f.3: DEVRES REL 000000001b480725 pcim_iomap_release (48 bytes) So the "devres_release_group(master->parent, NULL)" ends up freeing the pcim_iomap allocation. Upon next runtime resume, the audio driver will cause a page fault as the iomap alloc was released without the driver knowing about it. Fix this issue by using the "struct master" pointer as identifier for the devres group, and by closing the devres group after the master->ops->bind() call is done. This allows devres allocations done by the driver acting as master to be isolated from the binding state of the aggregate driver. This modifies the logic originally introduced in commit 9e1ccb4a7700 ("drivers/base: fix devres handling for master device") Cc: stable@vger.kernel.org BugLink: https://gitlab.freedesktop.org/drm/intel/-/issues/4136 Fixes: 9e1ccb4a7700 ("drivers/base: fix devres handling for master device") Signed-off-by: Kai Vehmanen Acked-by: Imre Deak Acked-by: Russell King (Oracle) --- drivers/base/component.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) V3 changes: - address feedback from Greg KH, add a Fixes tag and cc stable V2 changes: - after review form Imre and Russell, removing RFC tag - rebased on top of 5.15-rc2 (V1 was on drm-tip) - CI test results for V1 show that this patch fixes multiple failures in i915 unbind and module reload tests: https://patchwork.freedesktop.org/series/94889/ base-commit: 9e1ff307c779ce1f0f810c7ecce3d95bbae40896 diff --git a/drivers/base/component.c b/drivers/base/component.c index 5e79299f6c3f..870485cbbb87 100644 --- a/drivers/base/component.c +++ b/drivers/base/component.c @@ -246,7 +246,7 @@ static int try_to_bring_up_master(struct master *master, return 0; } - if (!devres_open_group(master->parent, NULL, GFP_KERNEL)) + if (!devres_open_group(master->parent, master, GFP_KERNEL)) return -ENOMEM; /* Found all components */ @@ -258,6 +258,7 @@ static int try_to_bring_up_master(struct master *master, return ret; } + devres_close_group(master->parent, NULL); master->bound = true; return 1; } @@ -282,7 +283,7 @@ static void take_down_master(struct master *master) { if (master->bound) { master->ops->unbind(master->parent); - devres_release_group(master->parent, NULL); + devres_release_group(master->parent, master); master->bound = false; } }