From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D01161D686 for ; Mon, 18 Sep 2023 16:07:55 +0000 (UTC) Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E242446AA for ; Mon, 18 Sep 2023 09:07:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=2D0A941kWzO8SqVobC80GHz9ouHUnRp6nlBz+6KUEAE=; b=uAYaHFv4MJ98GdYW7lwjZ4QGuK PmzMQyeV7v+L97ji2M7SU79WNWxoOA9R42P0rpV0B4J/X2ZZSEs0gmpomNp/zQVQBaKJKbMlqqXO5 te5sIWrh4oFzaQV0TspeAxsf15gOw8tm64e9cKv6zBB6h8zgDYTio6OHAMg39ahWWaRaUbYv5fw+t 5RgVH29RgqokN7/iLeSXxWVWPMkortzZHg3VQg4pox60M1btz9gJp2j9iJWSD1RI92QBlyvE/9Bu1 5+ZSMNRn1vvtCyCjycn0phzUQ32h53CdBTkm38waKD4QnZliiVI+romXBNYFZLZuW6reYqgFKlMMI x0sW4xDg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:34158) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qiDxN-0000HB-0R; Mon, 18 Sep 2023 14:06:29 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qiDxK-0000Ud-MQ; Mon, 18 Sep 2023 14:06:26 +0100 Date: Mon, 18 Sep 2023 14:06:26 +0100 From: "Russell King (Oracle)" To: Marek Szyprowski Cc: Andrew Lunn , Heiner Kallweit , chenhao418@huawei.com, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Jijie Shao , lanhao@huawei.com, liuyonglong@huawei.com, netdev@vger.kernel.org, Paolo Abeni , shenjian15@huawei.com, wangjie125@huawei.com, wangpeiyang1@huawei.com Subject: Re: [PATCH net-next 1/7] net: phy: always call phy_process_state_change() under lock Message-ID: References: <42ef8c8f-2fc0-a210-969b-7b0d648d8226@samsung.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42ef8c8f-2fc0-a210-969b-7b0d648d8226@samsung.com> Sender: Russell King (Oracle) X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Mon, Sep 18, 2023 at 02:33:04PM +0200, Marek Szyprowski wrote: > Hi Russell, > > On 14.09.2023 17:35, Russell King (Oracle) wrote: > > phy_stop() calls phy_process_state_change() while holding the phydev > > lock, so also arrange for phy_state_machine() to do the same, so that > > this function is called with consistent locking. > > > > Tested-by: Jijie Shao > > Signed-off-by: Russell King (Oracle) > > This change, merged to linux-next as commit 8da77df649c4 ("net: phy: > always call phy_process_state_change() under lock") introduces the > following deadlock with ASIX AX8817X USB driver: Yay, latent bug found... I guess this is asix_ax88772a_link_change_notify() which is causing the problem, and yes, that phy_start_aneg() needs to be the unlocked version (which we'll have to export.) This should fix it. diff --git a/drivers/net/phy/ax88796b.c b/drivers/net/phy/ax88796b.c index 0f1e617a26c9..eb74a8cf8df1 100644 --- a/drivers/net/phy/ax88796b.c +++ b/drivers/net/phy/ax88796b.c @@ -90,7 +90,7 @@ static void asix_ax88772a_link_change_notify(struct phy_device *phydev) */ if (phydev->state == PHY_NOLINK) { phy_init_hw(phydev); - phy_start_aneg(phydev); + _phy_start_aneg(phydev); } } diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index 93a8676dd8d8..a5fa077650e8 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -981,7 +981,7 @@ static int phy_check_link_status(struct phy_device *phydev) * If the PHYCONTROL Layer is operating, we change the state to * reflect the beginning of Auto-negotiation or forcing. */ -static int _phy_start_aneg(struct phy_device *phydev) +int _phy_start_aneg(struct phy_device *phydev) { int err; @@ -1002,6 +1002,7 @@ static int _phy_start_aneg(struct phy_device *phydev) return err; } +EXPORT_SYMBOL(_phy_start_aneg); /** * phy_start_aneg - start auto-negotiation for this PHY device diff --git a/include/linux/phy.h b/include/linux/phy.h index 1351b802ffcf..3cc52826f18e 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -1736,6 +1736,7 @@ void phy_detach(struct phy_device *phydev); void phy_start(struct phy_device *phydev); void phy_stop(struct phy_device *phydev); int phy_config_aneg(struct phy_device *phydev); +int _phy_start_aneg(struct phy_device *phydev); int phy_start_aneg(struct phy_device *phydev); int phy_aneg_done(struct phy_device *phydev); int phy_speed_down(struct phy_device *phydev, bool sync); -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!