From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C1505358378; Fri, 4 Sep 2026 06:08:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788502100; cv=none; b=UGmeClw366m10ilL2eoRQbxhnN8KMKmpJSzEuvq4BcEx5xKvBex9KOym1y6JJgtzpukItktOq3fKc484l0JAFOMovxw3KEN6SQdF0Gs21DGzH/LOElD0eqnRXrlr/n5KcWZezFRBQMnDPkA7EGbX1326Sb37QPhyKDGqn7V2JnA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788502100; c=relaxed/simple; bh=yWdCN5tKegO8ug0zGa9oLavPL9qp/PUSY9jQUmpdrdE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UfXBS7qVG8ei5t23HwBpIqd6DFVK7gTDNDUTrOBfEK6XPUbbc5pzvx0iRN+2ZjRONvWm2vuv6VD6GL0Abp2hkUp2cmNtuQy74My8LI4JGfasQ3aYjy7ZmKgAN7f/aGgctse0luc2qGcxdTczi0Jxqz0E3nL+v62dHvmszLjIAz8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sRCsr1DD; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="sRCsr1DD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 273D11F00A3E; Fri, 4 Sep 2026 06:08:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788502099; bh=uMcPD5yLPw4oI2j4f/M1H0Ib4U4IjK7t0uCxTSmM82M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sRCsr1DD9K/t0Rk98mz5dl0WZ8FeRCBl4QmHb+w8/MY0/VsO3jC/JP9eAavEnhG1V zE/M21Qwyf7UAndiTY4rMqdY86IHMaNv2llSvHCNYKaNT1yF08n6uGSK7BPI0q6Txb GU9HEi9hU4x/3nfPVDrJA71TOYnywEmjIq+fg40w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Karl Mehltretter , Frank Li Subject: [PATCH 6.12 045/403] serial: imx: serialize imx_uart_ports[] lifetime Date: Fri, 4 Sep 2026 06:57:28 +0200 Message-ID: <20260904045735.843573197@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045734.806166532@linuxfoundation.org> References: <20260904045734.806166532@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Karl Mehltretter commit 8b0b29fdcb47907ae0296b8fe829e918e05e300f upstream. imx_uart_probe() publishes its devm-allocated port in imx_uart_ports[] before uart_add_one_port() because console setup uses the table. The entry is not cleared when adding the port fails or after removal, leaving a dangling pointer. A sibling probe can register the shared console through that stale entry. This was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a sibling UART, unbinding the console UART and rebinding the sibling. Keep the entry valid through uart_remove_one_port(), then clear it. Protect port addition and removal together with their table updates so sibling operations cannot interleave. Reject an occupied slot rather than clobbering an active port during a duplicate-line probe. Fixes: dbff4e9ea2e8 ("IMX UART: remove statically initialized tables") Fixes: 9f322ad064f9 ("imx: serial: handle initialisation failure correctly") Reported-by: Sashiko Link: https://lore.kernel.org/all/20260719162850.043B41F000E9@smtp.kernel.org Link: https://lore.kernel.org/all/20260719222501.CB4CB1F000E9@smtp.kernel.org Cc: stable@vger.kernel.org Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260731181844.11330-6-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -2067,6 +2068,9 @@ static const struct uart_ops imx_uart_po static struct imx_port *imx_uart_ports[UART_NR]; +/* Held across uart_add/remove_one_port(); console callbacks must not take it. */ +static DEFINE_MUTEX(imx_uart_ports_lock); + #if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE) static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch) { @@ -2539,11 +2543,19 @@ static int imx_uart_probe(struct platfor } } - imx_uart_ports[sport->port.line] = sport; - platform_set_drvdata(pdev, sport); - ret = uart_add_one_port(&imx_uart_uart_driver, &sport->port); + scoped_guard(mutex, &imx_uart_ports_lock) { + if (imx_uart_ports[sport->port.line]) { + ret = -EBUSY; + } else { + imx_uart_ports[sport->port.line] = sport; + ret = uart_add_one_port(&imx_uart_uart_driver, + &sport->port); + if (ret) + imx_uart_ports[sport->port.line] = NULL; + } + } err_clk: clk_disable_unprepare(sport->clk_ipg); @@ -2555,7 +2567,9 @@ static void imx_uart_remove(struct platf { struct imx_port *sport = platform_get_drvdata(pdev); + guard(mutex)(&imx_uart_ports_lock); uart_remove_one_port(&imx_uart_uart_driver, &sport->port); + imx_uart_ports[sport->port.line] = NULL; } static void imx_uart_restore_context(struct imx_port *sport)