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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A03DC43334 for ; Sat, 9 Jul 2022 08:22:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229509AbiGIIWr (ORCPT ); Sat, 9 Jul 2022 04:22:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbiGIIWr (ORCPT ); Sat, 9 Jul 2022 04:22:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8571877483 for ; Sat, 9 Jul 2022 01:22:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 24FA460EB4 for ; Sat, 9 Jul 2022 08:22:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F570C3411C; Sat, 9 Jul 2022 08:22:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657354965; bh=oRzHdIcKhuWrj8K3zGGqQ5iXWMKvTQoNMVu5qGgajDI=; h=Subject:To:Cc:From:Date:From; b=jeJLlsEM25ap+J5DJ0FBfBxuOcNPfLzl9aWUdzg4bWLU1PYZ8citeLgI3RNF42j0L bZhJH7a+TojFm0S+MONnyMuC2EdB+XUhXNB35crscCR00St3rLA2AeZSOzTo2F6LNY ozP4pKVupv/k7mlr0Qw317lW18uZ6UdaSHWN8tW4= Subject: FAILED: patch "[PATCH] PM: runtime: Fix supplier device management during consumer" failed to apply to 4.19-stable tree To: rafael.j.wysocki@intel.com, gregkh@linuxfoundation.org, peter.wang@mediatek.com, stable@vger.kernel.org Cc: From: Date: Sat, 09 Jul 2022 10:22:42 +0200 Message-ID: <1657354962114216@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 887371066039011144b4a94af97d9328df6869a2 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 30 Jun 2022 21:16:41 +0200 Subject: [PATCH] PM: runtime: Fix supplier device management during consumer probe Because pm_runtime_get_suppliers() bumps up the rpm_active counter of each device link to a supplier of the given device in addition to bumping up the supplier's PM-runtime usage counter, a runtime suspend of the consumer device may case the latter to go down to 0 when pm_runtime_put_suppliers() is running on a remote CPU. If that happens after pm_runtime_put_suppliers() has released power.lock for the consumer device, and a runtime resume of that device takes place immediately after it, before pm_runtime_put() is called for the supplier, that pm_runtime_put() call may cause the supplier to be suspended even though the consumer is active. To prevent that from happening, modify pm_runtime_get_suppliers() to call pm_runtime_get_sync() for the given device's suppliers without touching the rpm_active counters of the involved device links Accordingly, modify pm_runtime_put_suppliers() to call pm_runtime_put() for the given device's suppliers without looking at the rpm_active counters of the device links at hand. [This is analogous to what happened before commit 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance").] Since pm_runtime_get_suppliers() sets supplier_preactivated for each device link where the supplier's PM-runtime usage counter has been incremented and pm_runtime_put_suppliers() calls pm_runtime_put() for the suppliers whose device links have supplier_preactivated set, the PM-runtime usage counter is balanced for each supplier and this is independent of the runtime suspend and resume of the consumer device. However, in case a device link with DL_FLAG_PM_RUNTIME set is dropped during the consumer device probe, so pm_runtime_get_suppliers() bumps up the supplier's PM-runtime usage counter, but it cannot be dropped by pm_runtime_put_suppliers(), make device_link_release_fn() take care of that. Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") Reported-by: Peter Wang Signed-off-by: Rafael J. Wysocki Reviewed-by: Greg Kroah-Hartman Reviewed-by: Peter Wang Cc: 5.1+ # 5.1+ diff --git a/drivers/base/core.c b/drivers/base/core.c index 58aa49527d3a..460d6f163e41 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -487,6 +487,16 @@ static void device_link_release_fn(struct work_struct *work) device_link_synchronize_removal(); pm_runtime_release_supplier(link); + /* + * If supplier_preactivated is set, the link has been dropped between + * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls + * in __driver_probe_device(). In that case, drop the supplier's + * PM-runtime usage counter to remove the reference taken by + * pm_runtime_get_suppliers(). + */ + if (link->supplier_preactivated) + pm_runtime_put_noidle(link->supplier); + pm_request_idle(link->supplier); put_device(link->consumer); diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 23cc4c377d77..949907e2e242 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1768,7 +1768,6 @@ void pm_runtime_get_suppliers(struct device *dev) if (link->flags & DL_FLAG_PM_RUNTIME) { link->supplier_preactivated = true; pm_runtime_get_sync(link->supplier); - refcount_inc(&link->rpm_active); } device_links_read_unlock(idx); @@ -1788,19 +1787,8 @@ void pm_runtime_put_suppliers(struct device *dev) list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, device_links_read_lock_held()) if (link->supplier_preactivated) { - bool put; - link->supplier_preactivated = false; - - spin_lock_irq(&dev->power.lock); - - put = pm_runtime_status_suspended(dev) && - refcount_dec_not_one(&link->rpm_active); - - spin_unlock_irq(&dev->power.lock); - - if (put) - pm_runtime_put(link->supplier); + pm_runtime_put(link->supplier); } device_links_read_unlock(idx);