From patchwork Fri Jul 1 20:47:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 12903778 X-Patchwork-Delegate: kuba@kernel.org 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 4F15FC433EF for ; Fri, 1 Jul 2022 20:50:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232255AbiGAUu4 (ORCPT ); Fri, 1 Jul 2022 16:50:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232366AbiGAUui (ORCPT ); Fri, 1 Jul 2022 16:50:38 -0400 Received: from mailout1.hostsharing.net (mailout1.hostsharing.net [IPv6:2a01:37:1000::53df:5fcc:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB9FE6EE90; Fri, 1 Jul 2022 13:50:24 -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 mailout1.hostsharing.net (Postfix) with ESMTPS id 61E47101920F1; Fri, 1 Jul 2022 22:50:20 +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 3855B61A6B50; Fri, 1 Jul 2022 22:50:20 +0200 (CEST) X-Mailbox-Line: From 5b38b04d9354d9c2e65e8b2c26e38ca8407d6bc7 Mon Sep 17 00:00:00 2001 Message-Id: <5b38b04d9354d9c2e65e8b2c26e38ca8407d6bc7.1656707954.git.lukas@wunner.de> In-Reply-To: References: From: Lukas Wunner Date: Fri, 1 Jul 2022 22:47:51 +0200 Subject: [PATCH net-next v2 1/3] usbnet: smsc95xx: Fix deadlock on runtime resume To: "David S. Miller" , Jakub Kicinski , Paolo Abeni , Eric Dumazet Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org, Steve Glendinning , UNGLinuxDriver@microchip.com, Oliver Neukum , Andre Edich , Oleksij Rempel , Oleksij Rempel , Martyn Welch , Gabriel Hojda , Christoph Fritz , Lino Sanfilippo , Philipp Rosenberger , Marek Szyprowski , Ferry Toth , Andrew Lunn , Alan Stern Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Commit 05b35e7eb9a1 ("smsc95xx: add phylib support") amended smsc95xx_resume() to call phy_init_hw(). That function waits for the device to runtime resume even though it is placed in the runtime resume path, causing a deadlock. The problem is that phy_init_hw() calls down to smsc95xx_mdiobus_read(), which never uses the _nopm variant of usbnet_read_cmd(). Commit b4df480f68ae ("usbnet: smsc95xx: add reset_resume function with reset operation") causes a similar deadlock on resume if the device was already runtime suspended when entering system sleep: That's because the commit introduced smsc95xx_reset_resume(), which calls down to smsc95xx_reset(), which neglects to use _nopm accessors. Fix by auto-detecting whether a device access is performed by the suspend/resume task_struct and use the _nopm variant if so. This works because the PM core guarantees that suspend/resume callbacks are run in task context. Stacktrace for posterity: INFO: task kworker/2:1:49 blocked for more than 122 seconds. Workqueue: usb_hub_wq hub_event schedule rpm_resume __pm_runtime_resume usb_autopm_get_interface usbnet_read_cmd __smsc95xx_read_reg __smsc95xx_phy_wait_not_busy __smsc95xx_mdio_read smsc95xx_mdiobus_read __mdiobus_read mdiobus_read smsc_phy_reset phy_init_hw smsc95xx_resume usb_resume_interface usb_resume_both usb_runtime_resume __rpm_callback rpm_callback rpm_resume __pm_runtime_resume usb_autoresume_device hub_event process_one_work Fixes: b4df480f68ae ("usbnet: smsc95xx: add reset_resume function with reset operation") Signed-off-by: Lukas Wunner Cc: stable@vger.kernel.org # v3.16+ Cc: Andre Edich --- drivers/net/usb/smsc95xx.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c index 35110814ba22..0316c80c3fc4 100644 --- a/drivers/net/usb/smsc95xx.c +++ b/drivers/net/usb/smsc95xx.c @@ -71,6 +71,7 @@ struct smsc95xx_priv { struct fwnode_handle *irqfwnode; struct mii_bus *mdiobus; struct phy_device *phydev; + struct task_struct *pm_task; }; static bool turbo_mode = true; @@ -80,13 +81,14 @@ MODULE_PARM_DESC(turbo_mode, "Enable multiple frames per Rx transaction"); static int __must_check __smsc95xx_read_reg(struct usbnet *dev, u32 index, u32 *data, int in_pm) { + struct smsc95xx_priv *pdata = dev->driver_priv; u32 buf; int ret; int (*fn)(struct usbnet *, u8, u8, u16, u16, void *, u16); BUG_ON(!dev); - if (!in_pm) + if (current != pdata->pm_task) fn = usbnet_read_cmd; else fn = usbnet_read_cmd_nopm; @@ -110,13 +112,14 @@ static int __must_check __smsc95xx_read_reg(struct usbnet *dev, u32 index, static int __must_check __smsc95xx_write_reg(struct usbnet *dev, u32 index, u32 data, int in_pm) { + struct smsc95xx_priv *pdata = dev->driver_priv; u32 buf; int ret; int (*fn)(struct usbnet *, u8, u8, u16, u16, const void *, u16); BUG_ON(!dev); - if (!in_pm) + if (current != pdata->pm_task) fn = usbnet_write_cmd; else fn = usbnet_write_cmd_nopm; @@ -1490,9 +1493,12 @@ static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message) u32 val, link_up; int ret; + pdata->pm_task = current; + ret = usbnet_suspend(intf, message); if (ret < 0) { netdev_warn(dev->net, "usbnet_suspend error\n"); + pdata->pm_task = NULL; return ret; } @@ -1732,6 +1738,7 @@ static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message) if (ret && PMSG_IS_AUTO(message)) usbnet_resume(intf); + pdata->pm_task = NULL; return ret; } @@ -1752,29 +1759,31 @@ static int smsc95xx_resume(struct usb_interface *intf) /* do this first to ensure it's cleared even in error case */ pdata->suspend_flags = 0; + pdata->pm_task = current; + if (suspend_flags & SUSPEND_ALLMODES) { /* clear wake-up sources */ ret = smsc95xx_read_reg_nopm(dev, WUCSR, &val); if (ret < 0) - return ret; + goto done; val &= ~(WUCSR_WAKE_EN_ | WUCSR_MPEN_); ret = smsc95xx_write_reg_nopm(dev, WUCSR, val); if (ret < 0) - return ret; + goto done; /* clear wake-up status */ ret = smsc95xx_read_reg_nopm(dev, PM_CTRL, &val); if (ret < 0) - return ret; + goto done; val &= ~PM_CTL_WOL_EN_; val |= PM_CTL_WUPS_; ret = smsc95xx_write_reg_nopm(dev, PM_CTRL, val); if (ret < 0) - return ret; + goto done; } phy_init_hw(pdata->phydev); @@ -1783,15 +1792,20 @@ static int smsc95xx_resume(struct usb_interface *intf) if (ret < 0) netdev_warn(dev->net, "usbnet_resume error\n"); +done: + pdata->pm_task = NULL; return ret; } static int smsc95xx_reset_resume(struct usb_interface *intf) { struct usbnet *dev = usb_get_intfdata(intf); + struct smsc95xx_priv *pdata = dev->driver_priv; int ret; + pdata->pm_task = current; ret = smsc95xx_reset(dev); + pdata->pm_task = NULL; if (ret < 0) return ret;