From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F34742389C4; Sun, 24 Nov 2024 13:51:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732456295; cv=none; b=Kj2m1p6xpkiAaZ1VUI/hFjYuXhRP8cMPZ5YchYLmUsa/CSG7oKRhklPb4MFx8m1qZZQqWqlk+wvg0O19uavhDeiVpWLKi5EAXBszxlm0OKNSfhhxo9EM6dFkhTLXHWvc+qfX6RUrqXGxZMEhEzp3XSmNN+rhlK8bJf5iwm6J1OI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732456295; c=relaxed/simple; bh=0k/HJW7lIikqX2d/so+Q+d9e7++AuEc20ExWdQlwupU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HfcFTZ27jn78Ick6izLsPWrhzSPNDSYiVi8PEs4UB80I1G6zRy6b3TniyT2g6bDXOQ5+yNsHV0MV5GwCo8hsUMPConJLaz5sIJgfUeOokZFvyuWOu6FVpdENbrqUS20xMzPqlQRYLfxwuj34DoKiqvcEdz7Qd0lRJg13JkhHUN4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tm7nwWgy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tm7nwWgy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35230C4CECC; Sun, 24 Nov 2024 13:51:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732456294; bh=0k/HJW7lIikqX2d/so+Q+d9e7++AuEc20ExWdQlwupU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tm7nwWgywH84uOl29sUueovAWN4VMQV8YYmeEu4XCNCMtHyRwBriJX+8xzD7qgJAO oCGMOiAyOOu+1KFF/zcRSDi6omw7QQ2y8GemuVF4jO5gV/PIl5JaLAJFv3dJgMxxtn Cp57O1V+dGZqxLgMs4rPD12JR4McoTJaMKVKLgss/cqyBOwCwVa2mnjC92QMIhU2qk V7Qd7fBK7LJ3ykGm2T44CliQbRCK2UQPZBjzor2Lu+/41g9LmHeIjJ7vkKquiXpLD/ icbZJfIrKXAPUm5QIrRqRxLFYcKUCreuBIS6ZDS/pIGEaNZnplzuw/+oC72IBG6BZy VDW15Ep1hWXWA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrew Lunn , Jakub Kicinski , Sasha Levin , olteanv@gmail.com, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, florian.fainelli@broadcom.com, alsi@bang-olufsen.dk, ansuelsmth@gmail.com, michal.vokac@ysoft.com, javier.carrasco.cruz@gmail.com, rmk+kernel@armlinux.org.uk, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.1 42/48] dsa: qca8k: Use nested lock to avoid splat Date: Sun, 24 Nov 2024 08:49:05 -0500 Message-ID: <20241124134950.3348099-42-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241124134950.3348099-1-sashal@kernel.org> References: <20241124134950.3348099-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.119 Content-Transfer-Encoding: 8bit From: Andrew Lunn [ Upstream commit 078e0d596f7b5952dad8662ace8f20ed2165e2ce ] qca8k_phy_eth_command() is used to probe the child MDIO bus while the parent MDIO is locked. This causes lockdep splat, reporting a possible deadlock. It is not an actually deadlock, because different locks are used. By making use of mutex_lock_nested() we can avoid this false positive. Signed-off-by: Andrew Lunn Link: https://patch.msgid.link/20241110175955.3053664-1-andrew@lunn.ch Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/dsa/qca/qca8k-8xxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c index 641692f716f86..47e9b2c303831 100644 --- a/drivers/net/dsa/qca/qca8k-8xxx.c +++ b/drivers/net/dsa/qca/qca8k-8xxx.c @@ -551,7 +551,7 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy, * We therefore need to lock the MDIO bus onto which the switch is * connected. */ - mutex_lock(&priv->bus->mdio_lock); + mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); /* Actually start the request: * 1. Send mdio master packet -- 2.43.0