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 961A0C19F2D for ; Sat, 13 Aug 2022 09:35:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238659AbiHMJfR (ORCPT ); Sat, 13 Aug 2022 05:35:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235278AbiHMJfQ (ORCPT ); Sat, 13 Aug 2022 05:35:16 -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 22B8FC7B for ; Sat, 13 Aug 2022 02:35:14 -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 84D0960C67 for ; Sat, 13 Aug 2022 09:35:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E07EC433D7; Sat, 13 Aug 2022 09:35:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660383313; bh=6pyRZ0Al8mjN/ekY8tOF7q1fs9bluMKccSz0vmpQOaw=; h=Subject:To:Cc:From:Date:From; b=ZSydSBsYdJwOYQNt7uLUciuZwcoxK2jU9f62OOXyb9RKnHdsjhNSEqfAW6T3mZ/50 6ZjLNbP/2fyginDjv+5Rwww5xq6LWrEScS2mXvuUErvuXlEg2Hbd2etXNHSpwCqmYY x9Um86eCj5fi5IscDPtcTPnuJtUrikljehHODfBo= Subject: FAILED: patch "[PATCH] usbnet: smsc95xx: Fix deadlock on runtime resume" failed to apply to 5.15-stable tree To: lukas@wunner.de, andre.edich@microchip.com, davem@davemloft.net Cc: From: Date: Sat, 13 Aug 2022 11:35:02 +0200 Message-ID: <1660383302137181@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 5.15-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 7b960c967f2aa01ab8f45c5a0bd78e754cffdeee Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Fri, 1 Jul 2022 22:47:51 +0200 Subject: [PATCH] usbnet: smsc95xx: Fix deadlock on runtime resume 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 Signed-off-by: David S. Miller 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;