From nobody Tue Sep 16 11:12:05 2025 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 C2821C4708E for ; Wed, 4 Jan 2023 13:09:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239384AbjADNJ3 (ORCPT ); Wed, 4 Jan 2023 08:09:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239398AbjADNIn (ORCPT ); Wed, 4 Jan 2023 08:08:43 -0500 Received: from mailout-taastrup.gigahost.dk (mailout-taastrup.gigahost.dk [46.183.139.199]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1371D1EC47; Wed, 4 Jan 2023 05:07:40 -0800 (PST) Received: from mailout.gigahost.dk (mailout.gigahost.dk [89.186.169.112]) by mailout-taastrup.gigahost.dk (Postfix) with ESMTP id 35AD31884546; Wed, 4 Jan 2023 13:07:38 +0000 (UTC) Received: from smtp.gigahost.dk (smtp.gigahost.dk [89.186.169.109]) by mailout.gigahost.dk (Postfix) with ESMTP id 14CB7250007B; Wed, 4 Jan 2023 13:07:38 +0000 (UTC) Received: by smtp.gigahost.dk (Postfix, from userid 1000) id 024879EC000E; Wed, 4 Jan 2023 13:07:37 +0000 (UTC) X-Screener-Id: 413d8c6ce5bf6eab4824d0abaab02863e8e3f662 Received: from fujitsu.vestervang (2-104-116-184-cable.dk.customer.tdc.net [2.104.116.184]) by smtp.gigahost.dk (Postfix) with ESMTPSA id A8A8491201E4; Wed, 4 Jan 2023 13:07:37 +0000 (UTC) From: "Hans J. Schultz" To: davem@davemloft.net, kuba@kernel.org Cc: netdev@vger.kernel.org, "Hans J. Schultz" , Andrew Lunn , Florian Fainelli , Vladimir Oltean , Eric Dumazet , Paolo Abeni , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2 net-next 2/3] net: dsa: mv88e6xxx: disable hold of chip lock for handling Date: Wed, 4 Jan 2023 14:06:02 +0100 Message-Id: <20230104130603.1624945-3-netdev@kapio-technology.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230104130603.1624945-1-netdev@kapio-technology.com> References: <20230104130603.1624945-1-netdev@kapio-technology.com> MIME-Version: 1.0 Organization: Westermo Network Technologies AB Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" As functions called under the interrupt handler will need to take the netlink lock, we need to release the chip lock before calling those functions as otherwise double lock deadlocks will occur as userspace calls towards the driver often take the netlink lock and then the chip lock. The deadlock would look like: Interrupt handler: chip lock taken, but cannot take netlink lock as userspace config call has netlink lock. Userspace config: netlink lock taken, but cannot take chip lock as the interrupt handler has the chip lock. Signed-off-by: Hans J. Schultz --- drivers/net/dsa/mv88e6xxx/global1_atu.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/net/dsa/mv88e6xxx/global1_atu.c b/drivers/net/dsa/mv88= e6xxx/global1_atu.c index 61ae2d61e25c..34203e112eef 100644 --- a/drivers/net/dsa/mv88e6xxx/global1_atu.c +++ b/drivers/net/dsa/mv88e6xxx/global1_atu.c @@ -409,11 +409,11 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_f= n(int irq, void *dev_id) =20 err =3D mv88e6xxx_g1_read_atu_violation(chip); if (err) - goto out; + goto out_unlock; =20 err =3D mv88e6xxx_g1_read(chip, MV88E6XXX_G1_ATU_OP, &val); if (err) - goto out; + goto out_unlock; =20 err =3D mv88e6xxx_g1_atu_fid_read(chip, &fid); if (err) @@ -421,11 +421,13 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_f= n(int irq, void *dev_id) =20 err =3D mv88e6xxx_g1_atu_data_read(chip, &entry); if (err) - goto out; + goto out_unlock; =20 err =3D mv88e6xxx_g1_atu_mac_read(chip, &entry); if (err) - goto out; + goto out_unlock; + + mv88e6xxx_reg_unlock(chip); =20 spid =3D entry.state; =20 @@ -449,13 +451,13 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_f= n(int irq, void *dev_id) fid); chip->ports[spid].atu_full_violation++; } - mv88e6xxx_reg_unlock(chip); =20 return IRQ_HANDLED; =20 -out: +out_unlock: mv88e6xxx_reg_unlock(chip); =20 +out: dev_err(chip->dev, "ATU problem: error %d while handling interrupt\n", err); return IRQ_HANDLED; --=20 2.34.1