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 58ACBC43334 for ; Wed, 29 Jun 2022 07:23:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231573AbiF2HXM (ORCPT ); Wed, 29 Jun 2022 03:23:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230516AbiF2HXG (ORCPT ); Wed, 29 Jun 2022 03:23:06 -0400 Received: from vps0.lunn.ch (vps0.lunn.ch [185.16.172.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC5C0222; Wed, 29 Jun 2022 00:23:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=udw9lHGmzoAvFePyLCTqIKD8e/mAeVeJzVZcMu5/Lq4=; b=j+WgdvbgwVAiXYEKAtG4WPjD0X 46phVxCdZseTfn5Sqq8rzFUj9MHWNX27GVEfZiR0NHLIGG84wfxUcMdEybxgfTXszXBobgLYgcyNU TK+U5pj9jP0tFtlxOEx/8NavELJT8zKDhgCEVxFpIERWhb+Oq7yvGRDDwejQbKGTS8Pc=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1o6S23-008gOb-QH; Wed, 29 Jun 2022 09:22:39 +0200 Date: Wed, 29 Jun 2022 09:22:39 +0200 From: Andrew Lunn To: Lukas Wunner Cc: "David S. Miller" , Jakub Kicinski , Paolo Abeni , Eric Dumazet , Heiner Kallweit , Russell King , Marek Szyprowski , Thomas Gleixner , 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" Subject: Re: [PATCH net v4] net: phy: Don't trigger state machine while in suspend Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 28, 2022 at 12:15:08PM +0200, Lukas Wunner wrote: > 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 Andrew