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 0C7243A9854; Fri, 4 Sep 2026 05:41:19 +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=1788500480; cv=none; b=jOkV4PiYb4FB0hOQrpfMyht0/BStFvdqwny243gveh55x90NRJBah7HNnYmtaY9JHuw9jfS/tZVS9RXxLSR63DekNyeN5yYN15iD2Bp588VZHM5zXLY+YdUqr47DWUo3qQeX+z7Agf5kmN/dsrJx6/ZAjL+iV82U6IIDPDJ/pr8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788500480; c=relaxed/simple; bh=tQsksN3QjL+a/5yesLZ551tv7mXo0LKsd6tXIL+uZK8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JvPcOX2GlCPvWuN4htL6iRjkELe0lnSIYuKXrF3+jcu06AjcFaXgcm+psTvUYbX0r0+cGVFnjLjrcrAG5nOHvtNwURxQw3zFWrKwJ3EMQBpsmS5Lwns30Ml/MyRZCOKmQ/tx6+xTwAGY0v+hgmRvmaC30k7jrlgD3oJuWTw8efI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=apJujrvZ; 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="apJujrvZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 645231F00A3D; Fri, 4 Sep 2026 05:41:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788500478; bh=2Jv51vG0dIknfWOTzPlISy06Hv6Nfu3IQSN8mG+81l0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=apJujrvZ3NIAerqsDUYKV0vhAolXl8fUAAw1Td3++41I5dDBq8rYRBjOPhEDWhEbt 3aWyVxiWzF3bTpT752475izz2JIMBDMsNgjowZWLMsyrRx1ZBez1JMDIcmxtWkDool Fzr2Jl9lo4oINxCmnVfNuhsLLxd/iH1pLpUX2fYc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Karl Mehltretter , Frank Li Subject: [PATCH 6.18 069/552] serial: imx: serialize imx_uart_ports[] lifetime Date: Fri, 4 Sep 2026 06:53:46 +0200 Message-ID: <20260904045749.414286502@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@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 6.18-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 @@ -2079,6 +2080,9 @@ 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) { @@ -2631,11 +2635,19 @@ 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); @@ -2647,7 +2659,9 @@ 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)