From nobody Mon Sep 28 19:24:52 2026 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [4.193.249.245]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 69AED3559CA; Wed, 19 Aug 2026 02:20:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=4.193.249.245 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787106037; cv=none; b=IzsSTf9SQM1C3FpW5QgjrOVtx3XfliEWtyVTSKR4ENOgpadRoQ5B87YYrmB8GmEDA4jwkAJbWKB4rJebastImHXNPeuvG2DdoQl3A/oonktVw9SnmUa+uwmMVEIE9jW08GKHF40KGVQvJZ0zBmYEcVLSRSuwY6wikZK3/m64SGQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787106037; c=relaxed/simple; bh=OXEufZy6jRZLSh8G4vNttI4g37voPQPxQMaRI9h5bR8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=mshWS/fm7I8zXzJnCdf0LqA6Y7HbWEZWShyB8wnfLW3wDp6J8hjyn0v01ziG0i3O84iZe4Y7ciIXyzJy8ctJoMCTzxArqGgzL6uccsr6Do0jV/CHjc6vz4g3nu7BI7yDJjShEFYHFSxyMpzIAUYf7BpiTCCDIMd/F4mIN7DpfFI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn; spf=pass smtp.mailfrom=zju.edu.cn; arc=none smtp.client-ip=4.193.249.245 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zju.edu.cn Received: from zju.edu.cn (unknown [10.98.66.117]) by mtasvr (Coremail) with SMTP id _____wC3gX3bEoVq7JmmAA--.42198S3; Wed, 19 Aug 2026 10:20:12 +0800 (CST) Received: from localhost.localdomain (unknown [10.98.66.117]) by mail-app1 (Coremail) with SMTP id yy_KCgCHiaPbEoVqNqb7Aw--.26282S2; Wed, 19 Aug 2026 10:20:11 +0800 (CST) From: Fan Wu To: Greg Kroah-Hartman , Jiri Slaby Cc: Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org, Fan Wu Subject: [PATCH] serial: imx: cancel RS485 trigger hrtimers in shutdown and remove Date: Wed, 19 Aug 2026 02:19:16 +0000 Message-Id: <20260819021916.442827-1-fanwu01@zju.edu.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: yy_KCgCHiaPbEoVqNqb7Aw--.26282S2 X-CM-SenderInfo: qrstjiaswqq6lmxovvfxof0/ X-CM-DELIVERINFO: =?B?hwMz9wXKKxbFmtjJiESix3B1w3vZ3A9ovKVTomAyoQazvoRs/NHSP8GI2EvgeEEW7R sfnVCjTgEH9dVomQuWcozCBBFqHGffgUj/kiZ79lR96Dn6tPZKPn6Kv4uFpy6/Kyifm6gz W5tHy1KOfp+zmAq5OVip9E6mavGmQbzmcFsnzP86 X-Coremail-Antispam: 1Uk129KBj93XoW7Kw48Kw4xXr4kJFWrCr47Jrc_yoW8tryxpF Z2gr9IkFWqqa1SvanrAF1jgFW5twn3AFW7Gr1xGa4Fv398JF1FkF13KFZYvFW7t34UtFWa vr48tr4DCFZrtFXCm3ZEXasCq-sJn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUPjb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Cr1j6rxdM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2vYz4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6x kI12xvs2x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v2 6r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2 Ij64vIr41lF7xvr2IYc2Ij64vIr40E4x8a64kEw24lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F 4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY 6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU7gAwDUUUU Content-Type: text/plain; charset="utf-8" The rs485 delay hrtimers trigger_start_tx and trigger_stop_tx are embedded in the devm allocated struct imx_port, and their callbacks reach the port through container_of() and touch registers under the port lock. Nothing cancels them synchronously: the tx paths only call hrtimer_try_to_cancel(), which does not wait for a running callback, and the bounded wait in imx_uart_shutdown() can give up, force tx_state to OFF, and leave a timer armed. After imx_uart_remove() returns, devm frees the port and a late callback dereferences freed memory. Cancel both timers at the end of imx_uart_shutdown(), after the port lock is dropped and before the clocks are disabled, and again in imx_uart_remove() before the devm free: serial core does not call the driver shutdown on every path that reaches remove(). This issue was found by an in-house static analysis tool. Fixes: bd78ecd6056d ("serial: imx: use hrtimers for rs485 delays") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu --- drivers/tty/serial/imx.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 251a50c8aa38..86c99f73c50a 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1707,6 +1707,10 @@ static void imx_uart_shutdown(struct uart_port *port) =20 uart_port_unlock_irqrestore(&sport->port, flags); =20 + /* The rs485 trigger callbacks take the port lock and touch registers. */ + hrtimer_cancel(&sport->trigger_start_tx); + hrtimer_cancel(&sport->trigger_stop_tx); + clk_disable_unprepare(sport->clk_per); clk_disable_unprepare(sport->clk_ipg); } @@ -2649,6 +2653,10 @@ static void imx_uart_remove(struct platform_device *= pdev) struct imx_port *sport =3D platform_get_drvdata(pdev); =20 uart_remove_one_port(&imx_uart_uart_driver, &sport->port); + + /* Serial core can reach remove() without calling the driver shutdown. */ + hrtimer_cancel(&sport->trigger_start_tx); + hrtimer_cancel(&sport->trigger_stop_tx); } =20 static void imx_uart_restore_context(struct imx_port *sport)