From patchwork Tue Jun 28 10:15:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 12898044 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 96CF1C433EF for ; Tue, 28 Jun 2022 10:15:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344727AbiF1KPo (ORCPT ); Tue, 28 Jun 2022 06:15:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343964AbiF1KPh (ORCPT ); Tue, 28 Jun 2022 06:15:37 -0400 Received: from mailout3.hostsharing.net (mailout3.hostsharing.net [IPv6:2a01:4f8:150:2161:1:b009:f236:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B7A011822; Tue, 28 Jun 2022 03:15:35 -0700 (PDT) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS DV RSA Mixed SHA256 2020 CA-1" (verified OK)) by mailout3.hostsharing.net (Postfix) with ESMTPS id D0006101E6AA3; Tue, 28 Jun 2022 12:15:29 +0200 (CEST) Received: from localhost (unknown [89.246.108.87]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 99F0061DA94E; Tue, 28 Jun 2022 12:15:29 +0200 (CEST) X-Mailbox-Line: From b7f386d04e9b5b0e2738f0125743e30676f309ef Mon Sep 17 00:00:00 2001 Message-Id: From: Lukas Wunner Date: Tue, 28 Jun 2022 12:15:08 +0200 Subject: [PATCH net v4] net: phy: Don't trigger state machine while in suspend To: "David S. Miller" , Jakub Kicinski , Paolo Abeni , Eric Dumazet , Andrew Lunn , Heiner Kallweit , Russell King , Marek Szyprowski , Thomas Gleixner Cc: netdev@vger.kernel.org, Steve Glendinning , UNGLinuxDriver@microchip.com, Oliver Neukum , Andre Edich , Oleksij Rempel , Martyn Welch , Gabriel Hojda , Christoph Fritz , Lino Sanfilippo , Philipp Rosenberger , Ferry Toth , Krzysztof Kozlowski , linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, "Rafael J. Wysocki" Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org Upon system sleep, mdio_bus_phy_suspend() stops the phy_state_machine(), but subsequent interrupts may retrigger it: They may have been left enabled to facilitate wakeup and are not quiesced until the ->suspend_noirq() phase. Unwanted interrupts may hence occur between mdio_bus_phy_suspend() and dpm_suspend_noirq(), as well as between dpm_resume_noirq() and mdio_bus_phy_resume(). Retriggering the phy_state_machine() through an interrupt is not only undesirable for the reason given in mdio_bus_phy_suspend() (freezing it midway with phydev->lock held), but also because the PHY may be inaccessible after it's suspended: Accesses to USB-attached PHYs are blocked once usb_suspend_both() clears the can_submit flag and PHYs on PCI network cards may become inaccessible upon suspend as well. Amend phy_interrupt() to avoid triggering the state machine if the PHY is suspended. Signal wakeup instead if the attached net_device or its parent has been configured as a wakeup source. (Those conditions are identical to mdio_bus_phy_may_suspend().) Postpone handling of the interrupt until the PHY has resumed. Before stopping the phy_state_machine() in mdio_bus_phy_suspend(), wait for a concurrent phy_interrupt() to run to completion. That is necessary because phy_interrupt() may have checked the PHY's suspend status before the system sleep transition commenced and it may thus retrigger the state machine after it was stopped. Likewise, after re-enabling interrupt handling in mdio_bus_phy_resume(), wait for a concurrent phy_interrupt() to complete to ensure that interrupts which it postponed are properly rerun. The issue was exposed by commit 1ce8b37241ed ("usbnet: smsc95xx: Forward PHY interrupts to PHY driver to avoid polling"), but has existed since forever. Fixes: 541cd3ee00a4 ("phylib: Fix deadlock on resume") Link: https://lore.kernel.org/netdev/a5315a8a-32c2-962f-f696-de9a26d30091@samsung.com/ Reported-by: Marek Szyprowski Tested-by: Marek Szyprowski Signed-off-by: Lukas Wunner Acked-by: Rafael J. Wysocki Cc: stable@vger.kernel.org # v2.6.33+ Reviewed-by: Andrew Lunn --- Changes v3 -> v4: * Fix sha1 in commit message * Add correct Fixes tag Changes v2 -> v3: * Add stable designation * Add Acked-by tag (Rafael) Changes v1 -> v2: * Extend rationale in commit message * Drop incorrect Fixes tag, add Tested-by tag (Marek) Link to v3: https://lore.kernel.org/netdev/c5595bdb20625382538816c2e6d917d95c62e09b.1656322883.git.lukas@wunner.de/ drivers/net/phy/phy.c | 23 +++++++++++++++++++++++ drivers/net/phy/phy_device.c | 23 +++++++++++++++++++++++ include/linux/phy.h | 6 ++++++ 3 files changed, 52 insertions(+) diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index ef62f357b76d..8d3ee3a6495b 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -976,6 +977,28 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat) struct phy_driver *drv = phydev->drv; irqreturn_t ret; + /* Wakeup interrupts may occur during a system sleep transition. + * Postpone handling until the PHY has resumed. + */ + if (IS_ENABLED(CONFIG_PM_SLEEP) && phydev->irq_suspended) { + struct net_device *netdev = phydev->attached_dev; + + if (netdev) { + struct device *parent = netdev->dev.parent; + + if (netdev->wol_enabled) + pm_system_wakeup(); + else if (device_may_wakeup(&netdev->dev)) + pm_wakeup_dev_event(&netdev->dev, 0, true); + else if (parent && device_may_wakeup(parent)) + pm_wakeup_dev_event(parent, 0, true); + } + + phydev->irq_rerun = 1; + disable_irq_nosync(irq); + return IRQ_HANDLED; + } + mutex_lock(&phydev->lock); ret = drv->handle_interrupt(phydev); mutex_unlock(&phydev->lock); diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 431a8719c635..46acddd865a7 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -278,6 +278,15 @@ static __maybe_unused int mdio_bus_phy_suspend(struct device *dev) if (phydev->mac_managed_pm) return 0; + /* Wakeup interrupts may occur during the system sleep transition when + * the PHY is inaccessible. Set flag to postpone handling until the PHY + * has resumed. Wait for concurrent interrupt handler to complete. + */ + if (phy_interrupt_is_valid(phydev)) { + phydev->irq_suspended = 1; + synchronize_irq(phydev->irq); + } + /* We must stop the state machine manually, otherwise it stops out of * control, possibly with the phydev->lock held. Upon resume, netdev * may call phy routines that try to grab the same lock, and that may @@ -315,6 +324,20 @@ static __maybe_unused int mdio_bus_phy_resume(struct device *dev) if (ret < 0) return ret; no_resume: + if (phy_interrupt_is_valid(phydev)) { + phydev->irq_suspended = 0; + synchronize_irq(phydev->irq); + + /* Rerun interrupts which were postponed by phy_interrupt() + * because they occurred during the system sleep transition. + */ + if (phydev->irq_rerun) { + phydev->irq_rerun = 0; + enable_irq(phydev->irq); + irq_wake_thread(phydev->irq, phydev); + } + } + if (phydev->attached_dev && phydev->adjust_link) phy_start_machine(phydev); diff --git a/include/linux/phy.h b/include/linux/phy.h index 508f1149665b..b09f7d36cff2 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -572,6 +572,10 @@ struct macsec_ops; * @mdix_ctrl: User setting of crossover * @pma_extable: Cached value of PMA/PMD Extended Abilities Register * @interrupts: Flag interrupts have been enabled + * @irq_suspended: Flag indicating PHY is suspended and therefore interrupt + * handling shall be postponed until PHY has resumed + * @irq_rerun: Flag indicating interrupts occurred while PHY was suspended, + * requiring a rerun of the interrupt handler after resume * @interface: enum phy_interface_t value * @skb: Netlink message for cable diagnostics * @nest: Netlink nest used for cable diagnostics @@ -626,6 +630,8 @@ struct phy_device { /* Interrupts are enabled */ unsigned interrupts:1; + unsigned irq_suspended:1; + unsigned irq_rerun:1; enum phy_state state;