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 4EBD3C32772 for ; Tue, 23 Aug 2022 09:49:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242786AbiHWJtC (ORCPT ); Tue, 23 Aug 2022 05:49:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352489AbiHWJq3 (ORCPT ); Tue, 23 Aug 2022 05:46:29 -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 763909080D; Tue, 23 Aug 2022 01:43:59 -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 7F93361377; Tue, 23 Aug 2022 08:43:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DDD5C433D6; Tue, 23 Aug 2022 08:43:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661244219; bh=MKtkNLnOpsU+iTzTYMESxp1iv6KPokCGsvYIOzSz0VY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iuSnnJ9ana6Bf9BjQ0Hv7b1WxSZCZCchijVrFoihWazp9Y2+1itKBjZPHS0pq/d71 +tojy+f0Ft3WJUdMfeGxM9/hQijg+0GBLIkkRfvBcMt8+M/uQdRjTXsu01BChgOTQW fbSXC+Z3nFiBZVbgLqbVEPLT7wG4TaI2EiXlhkpw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Florian Fainelli , Jakub Kicinski Subject: [PATCH 5.15 058/244] net: phy: Warn about incorrect mdio_bus_phy_resume() state Date: Tue, 23 Aug 2022 10:23:37 +0200 Message-Id: <20220823080101.009863270@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080059.091088642@linuxfoundation.org> References: <20220823080059.091088642@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Florian Fainelli commit 744d23c71af39c7dc77ac7c3cac87ae86a181a85 upstream. Calling mdio_bus_phy_resume() with neither the PHY state machine set to PHY_HALTED nor phydev->mac_managed_pm set to true is a good indication that we can produce a race condition looking like this: CPU0 CPU1 bcmgenet_resume -> phy_resume -> phy_init_hw -> phy_start -> phy_resume phy_start_aneg() mdio_bus_phy_resume -> phy_resume -> phy_write(..., BMCR_RESET) -> usleep() -> phy_read() with the phy_resume() function triggering a PHY behavior that might have to be worked around with (see bf8bfc4336f7 ("net: phy: broadcom: Fix brcm_fet_config_init()") for instance) that ultimately leads to an error reading from the PHY. Fixes: fba863b81604 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM") Signed-off-by: Florian Fainelli Link: https://lore.kernel.org/r/20220801233403.258871-1-f.fainelli@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/phy/phy_device.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -315,6 +315,12 @@ static __maybe_unused int mdio_bus_phy_r phydev->suspended_by_mdio_bus = 0; + /* If we managed to get here with the PHY state machine in a state other + * than PHY_HALTED this is an indication that something went wrong and + * we should most likely be using MAC managed PM and we are not. + */ + WARN_ON(phydev->state != PHY_HALTED && !phydev->mac_managed_pm); + ret = phy_init_hw(phydev); if (ret < 0) return ret;