From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szelinsky.de (szelinsky.de [85.214.127.56]) (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 888BD44C65C; Sun, 18 Oct 2026 08:23:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=85.214.127.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792311812; cv=none; b=a/NKvTeY7TijCMohi6nmm7FUWHLa0nQVdHQyJi4hvif7hhro1l6cXd1eTf4HRdmlkYerhbA6OtGmdEOjdUhcogZlbrCaTAS+T2zJamSlFjJ9xL+KgjFGv48aSnPgAEnf5h9R7M7wDQUI6YxjCy8mwzvjOR0fhf2cc2dADRijdmw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792311812; c=relaxed/simple; bh=vpFRz9H9DErjcP/Ow9slPCX9jKa1X1nWSAqsvJW1AsM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NuAkn8otIVZB9H+0IQe0dTgPdLMgOAbXy1JCdcGiN/bVBkaTK0esgg/s6y2j5yiyeIl7NdLnuMT+Zt1j9zx8XaYhxRDEtn8Z3auRrkA1Wc3YM8SgFNcDkjNPfBLH5vFh+yIViR0gvy0PjmdHRu73rSP1+isj8wrrG8iPX86kun0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=szelinsky.de; spf=pass smtp.mailfrom=szelinsky.de; dkim=temperror (0-bit key) header.d=szelinsky.de header.i=@szelinsky.de header.b=HiJkquQO; arc=none smtp.client-ip=85.214.127.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=szelinsky.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=szelinsky.de Authentication-Results: smtp.subspace.kernel.org; dkim=temperror (0-bit key) header.d=szelinsky.de header.i=@szelinsky.de header.b="HiJkquQO" Received: from localhost (localhost [127.0.0.1]) by szelinsky.de (Postfix) with ESMTP id 3BA96E83961; Sun, 18 Oct 2026 10:23:28 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szelinsky.de; s=mail; t=1792311808; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oH80DEF1KRqV74bKoPbKxH4F/ryu9Wa5A7nbGrLtt0c=; b=HiJkquQO3F9BcYCJ2d7XTF48aV0IrpCuLsoeTjoBQBFLdjxAcpsS3pdC/vRqY82Fpx6505 kQUtzF061juh1Tn0L9DJKzVoh5CAFhu3312zk9J9sNsFaw8tiA/ZviGr1XI03WqHrhd9/B SdIZWMvz2OenO0p5wcN2ResuT1dtIb1f4Qp6XJvnpbjrZZPCRzeltqVH5O8OE/T4hGkuGl 8jdenmPbKtB29N36O1AbzSV+tDj58UxYSPvK1Q3M+YALkNiL9rK/HA6ard6zKyitLGcIVQ lwQxM9HXWiPUHSuVVc88fNlnM6Y2chupKgv/Mbl3jAgUz0aYGuOsiBAWcAxoQg== X-Virus-Scanned: Debian amavis at szelinsky.de Received: from szelinsky.de ([127.0.0.1]) by localhost (szelinsky.de [127.0.0.1]) (amavis, port 10025) with ESMTP id SHM9o0tbKkJX; Sun, 18 Oct 2026 10:23:28 +0200 (CEST) Received: from p14sgen5.netbird.selfhosted (dslb-088-070-183-026.088.070.pools.vodafone-ip.de [88.70.183.26]) by szelinsky.de (Postfix) with ESMTPSA; Sun, 18 Oct 2026 10:23:27 +0200 (CEST) From: Carlo Szelinsky To: Oleksij Rempel , Kory Maincent , Andrew Lunn , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Piotr Kubik , Sai Krishna , Simon Horman , Kyle Swenson , netdev-bot+sashiko@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Carlo Szelinsky Subject: [PATCH net 04/10] net: pse-pd: do not reach a freed PHY from the notification worker Date: Sun, 18 Oct 2026 10:23:07 +0200 Message-ID: <20261018082314.48950-5-github@szelinsky.de> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261018082314.48950-1-github@szelinsky.de> References: <20261018082314.48950-1-github@szelinsky.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The notification worker holds a reference on the pse_control, but not on the PHY that psec->attached_phydev points to. If the PHY is removed while the worker runs, the pse_control survives and the worker reads the freed PHY. The same happens without a race when two PHYs share one PI: attached_phydev keeps pointing at the first PHY after it is removed. pse_control_put() unlinks and frees a pse_control under pse_list_mutex, and phy_device_remove() calls it before the PHY is freed. So instead of taking a reference, let the worker look the pse_control up and use attached_phydev under pse_list_mutex. This nests pse_list_mutex inside rtnl; nothing under pse_list_mutex takes rtnl. For a PI shared by two PHYs there is no single netdev to report to, so clear attached_phydev when a second PHY takes the pse_control, and warn. Events for that PI are then no longer reported, even after one PHY goes away. Failing the second PHY instead would fail its whole MDIO bus. Fixes: fa2f0454174c ("net: pse-pd: Introduce attached_phydev to pse control") Signed-off-by: Carlo Szelinsky --- drivers/net/pse-pd/pse_core.c | 42 ++++++++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 11 deletions(-) diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c index 65a41c517b35..336f00d82b5f 100644 --- a/drivers/net/pse-pd/pse_core.c +++ b/drivers/net/pse-pd/pse_core.c @@ -238,24 +238,22 @@ static int of_load_pse_pis(struct pse_controller_dev *pcdev) * @pcdev: a pointer to the PSE * @id: index of the PSE control * - * Return: pse_control pointer or NULL. The device returned has had a - * reference added and the pointer is safe until the user calls - * pse_control_put() to indicate they have finished with it. + * Must be called with pse_list_mutex held. No reference is taken: the + * pointer is only valid until pse_list_mutex is released. + * + * Return: pse_control pointer or NULL. */ static struct pse_control * pse_control_find_by_id(struct pse_controller_dev *pcdev, int id) { struct pse_control *psec; - mutex_lock(&pse_list_mutex); + lockdep_assert_held(&pse_list_mutex); + list_for_each_entry(psec, &pcdev->pse_control_head, list) { - if (psec->id == id) { - kref_get(&psec->refcnt); - mutex_unlock(&pse_list_mutex); + if (psec->id == id) return psec; - } } - mutex_unlock(&pse_list_mutex); return NULL; } @@ -268,6 +266,7 @@ pse_control_find_by_id(struct pse_controller_dev *pcdev, int id) static struct net_device *pse_control_get_netdev(struct pse_control *psec) { ASSERT_RTNL(); + lockdep_assert_held(&pse_list_mutex); if (!psec || !psec->attached_phydev) return NULL; @@ -1020,13 +1019,21 @@ static void pse_send_ntf_worker(struct work_struct *work) struct net_device *netdev; struct pse_control *psec; - psec = pse_control_find_by_id(pcdev, ntf.id); + /* A pse_control is only on the list while the PHY it was + * handed to holds it: the PHY's pse_control_put() unlinks + * and frees it under pse_list_mutex before the PHY itself + * can be freed. Holding the mutex across the lookup and the + * attached_phydev dereference therefore keeps the PHY alive, + * which a reference on the pse_control alone would not. + */ rtnl_lock(); + mutex_lock(&pse_list_mutex); + psec = pse_control_find_by_id(pcdev, ntf.id); netdev = pse_control_get_netdev(psec); if (netdev) ethnl_pse_send_ntf(netdev, ntf.notifs); + mutex_unlock(&pse_list_mutex); rtnl_unlock(); - pse_control_put(psec); } } @@ -1417,6 +1424,19 @@ pse_control_get_internal(struct pse_controller_dev *pcdev, unsigned int index, list_for_each_entry(psec, &pcdev->pse_control_head, list) { if (psec->id == index) { + /* attached_phydev can only name one PHY. If a second + * one shares the PI, either may be removed first and + * leave it pointing at a freed phy_device, so stop + * reporting events for this PI instead. + */ + if (psec->attached_phydev && + psec->attached_phydev != phydev) { + dev_warn(pcdev->dev, + "PI %u shared by several PHYs, not reporting its events\n", + index); + psec->attached_phydev = NULL; + } + kref_get(&psec->refcnt); return psec; } -- 2.43.0