From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794342067; b=UWLHk2Cq6Ulv755QR4pt+OODry8/r1haBBOVK0XlJSXt2SiEkYWas9cTE21w2+O+G+Rv EHe5DHRa2l8Oy/YDQWIxktj+hhOlToZgGSEHTBOUPTbO6cxabKxq5tM8DJoXB2AlskaD/ IyQ5IlUCCh+77OTnRlUV772GPgsgjqdPmwuBqHoGOVfL0sNR/1G9zcNQp53a7z7xWt1Q6 JpQW2ltKKYKB3JC3L3a5NED1OnCAqc5AvR7YRiPcPuUOOF79kdRLUXdihLQVJWsCPIh7C YL3LH0dnRTc5zh4rgMgkuNcC4ecnt75onJY1EIfBDb1LZ7+7OLWJVNUvW6pTjovvwtA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794342067; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=OnSG3k2hqxkxZB3IevfH7sBqErCAgQcjtQFeoWNFTTo=; b=S/NoHmBk/dxGnoa60MQ3Lni/bRfA5FwkFfr+qwC0DK+1nn0PX8MJWBiI58fsJWvf350b InY1EvDwxKj7wS7dCUyxFUxfS1Coxv71vHqa+zcVINzttjjbjKROuBOJU7MQo1aBJSKSx YWTP1fjhrOc+G549KiMl884IRyV5go7ElHZysAoF6V1ZJVtrNeLkQ6JYBpnPFyI1EbLYy H9nRSEvXlbs2YVpWK0kYaYzMjBomgFrsgn4If4ASZGFIHjkF5tZ/y63MV33u69g51qYwV SkLJFhIGYhU3qNDyiXPWTZOKTQoNaH2QoOiB323uIPGk+uqLqG6TvE98W9V3poWfnJQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=i9rYHFmX; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5232B606AE07 for ; Tue, 10 Nov 2026 20:21:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=i9rYHFmX Received: by smtp.kernel.org (Postfix) with ESMTPSA id 678AF1F008BF; Tue, 10 Nov 2026 20:21:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794342066; bh=OnSG3k2hqxkxZB3IevfH7sBqErCAgQcjtQFeoWNFTTo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=i9rYHFmXQ2QuOT1w/dPIP25J7vvQwyZ6iIgYdKz2hKB0mVgRB63uf/Wi7ahu/LuAZ B5ZGcOjO4+TR5TuC0oDjUfJ2NWzx63lNDrcdCgeEaqVJ/byIcFtUxANXeBNPCNOWt1 b4Z7mXP7oKKxZE3Ua2votos4DSIcmiJcWHJCa1zWeEzoTxamtnwHTw3zgsZUjea7vg 22IpzusVi4MCI55nMXsWmFwJ3ZHX03rQRS1hF9TnMdnR2GR7622XgsvFIU1/fp14y0 U4/RVJ8s2TUnQ85Zt3hFeU49pS+7s3FVzrzD/05a/9xWZzfUjbhHB7DuR6gefQm5k0 7+NGyaiNr+YMg== From: Sasha Levin To: stable@vger.kernel.org Cc: "Jiri Slaby (SUSE)" , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.6.y 4/4] serial: 8250_exar: store the GPIO platform device in struct exar8250 Date: Tue, 10 Nov 2026 15:21:02 -0500 Message-ID: <20261110202051.3754797-4-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261110202051.3754797-1-sashal@kernel.org> References: <20261107053424-failed-6.6-33d337816e00@kernel.org> <20261110202051.3754797-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Jiri Slaby (SUSE)" [ Upstream commit 33d337816e00994daaf670243186d9e537ee090d ] The GPIO platform device is registered via platform->register_gpio() when port 0 is being set up. It is stored to port->port.private_data of the on-stack uart template (and from there it is copied into every registered port). pci_xr17v35x_exit() then fetches it back by serial8250_get_port(priv->line[0]). But port 0 does not have to exist at that point. If serial8250_register_8250_port() fails for port 0, priv->line[0] holds a negative error code. The probe still succeeds (it only breaks the loop), so on unbind, priv->line[0] (a negative value) is passed to serial8250_get_port(). The GPIO device is never unregistered and a bogus port is accessed. The same problem would also occur after the planned conversion of serial8250_register_8250_port() to return a uart port instead of a line. As Sashiko pointed out in that case: If board->setup() fails for the first port (i=0) in exar_pci_probe(), priv->uport[0] remains NULL. If serial8250_register_8250_port() fails, it returns an ERR_PTR. In either case, the loop breaks and probe returns success. When the device is later unbound, pci_xr17v35x_exit() unconditionally passes priv->uport[0] to platform->unregister_gpio(), which will dereference it without checking for validity. The GPIO device belongs to the PCI device, not to any particular port. So store it in a new struct exar8250::gpio member. Pass priv to both ->register_gpio() and ->unregister_gpio(), so that pci_xr17v35x_exit() does not need to look up any port at all. Signed-off-by: Jiri Slaby (SUSE) Fixes: d0aeaa83f0b0 ("serial: exar: split out the exar code from 8250_pci") Link: https://lore.kernel.org/all/sashiko-outbox-166269@kernel.org/ Assisted-by: LLM Cc: stable@vger.kernel.org Link: https://patch.msgid.link/03a8b5c71614fc672fef1e55c083bda6c73b5bf3.1791873876.git.jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/8250/8250_exar.c | 36 ++++++++++++++--------------- 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c index aa72d252c6bcb..c15cf3cc87144 100644 --- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -169,8 +169,9 @@ struct exar8250_platform { int (*rs485_config)(struct uart_port *port, struct ktermios *termios, struct serial_rs485 *rs485); const struct serial_rs485 *rs485_supported; - int (*register_gpio)(struct pci_dev *pcidev, struct uart_8250_port *port); - void (*unregister_gpio)(struct uart_8250_port *port); + int (*register_gpio)(struct exar8250 *priv, struct pci_dev *pcidev, + struct uart_8250_port *port); + void (*unregister_gpio)(struct exar8250 *priv); }; /** @@ -194,6 +195,7 @@ struct exar8250 { unsigned int nr; struct exar8250_board *board; void __iomem *virt; + struct platform_device *gpio; int line[]; }; @@ -452,22 +454,21 @@ static const struct software_node exar_gpio_node = { .properties = exar_gpio_properties, }; -static int xr17v35x_register_gpio(struct pci_dev *pcidev, struct uart_8250_port *port) +static int xr17v35x_register_gpio(struct exar8250 *priv, struct pci_dev *pcidev, + struct uart_8250_port *port) { if (pcidev->vendor == PCI_VENDOR_ID_EXAR) - port->port.private_data = - __xr17v35x_register_gpio(pcidev, &exar_gpio_node); + priv->gpio = __xr17v35x_register_gpio(pcidev, &exar_gpio_node); return 0; } -static void xr17v35x_unregister_gpio(struct uart_8250_port *port) +static void xr17v35x_unregister_gpio(struct exar8250 *priv) { - if (!port->port.private_data) - return; - - __xr17v35x_unregister_gpio(port->port.private_data); - port->port.private_data = NULL; + if (priv->gpio) { + __xr17v35x_unregister_gpio(priv->gpio); + priv->gpio = NULL; + } } static int generic_rs485_config(struct uart_port *port, struct ktermios *termios, @@ -550,8 +551,9 @@ static const struct software_node iot2040_gpio_node = { .properties = iot2040_gpio_properties, }; -static int iot2040_register_gpio(struct pci_dev *pcidev, - struct uart_8250_port *port) +static int iot2040_register_gpio(struct exar8250 *priv, + struct pci_dev *pcidev, + struct uart_8250_port *port) { u8 __iomem *p = port->port.membase; @@ -560,8 +562,7 @@ static int iot2040_register_gpio(struct pci_dev *pcidev, writeb(IOT2040_UARTS_ENABLE, p + UART_EXAR_MPIOLVL_15_8); writeb(IOT2040_UARTS_GPIO_HI_MODE, p + UART_EXAR_MPIOSEL_15_8); - port->port.private_data = - __xr17v35x_register_gpio(pcidev, &iot2040_gpio_node); + priv->gpio = __xr17v35x_register_gpio(pcidev, &iot2040_gpio_node); return 0; } @@ -635,7 +636,7 @@ pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev, /* Setup Multipurpose Input/Output pins. */ setup_gpio(pcidev, p); - ret = platform->register_gpio(pcidev, port); + ret = platform->register_gpio(priv, pcidev, port); } return ret; @@ -645,9 +646,8 @@ static void pci_xr17v35x_exit(struct pci_dev *pcidev) { const struct exar8250_platform *platform = exar_get_platform(); struct exar8250 *priv = pci_get_drvdata(pcidev); - struct uart_8250_port *port = serial8250_get_port(priv->line[0]); - platform->unregister_gpio(port); + platform->unregister_gpio(priv); } static inline void exar_misc_clear(struct exar8250 *priv) -- 2.53.0