From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8F53BC55174 for ; Fri, 31 Jul 2026 18:19:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6m+8w0QVgGm8urXe/cU07WfU5xAZ+QJVFPsiFH0egMo=; b=NvxLBoOt86zGOW8/YtrfEDr/z+ j6LjKmEqpFZdP238l1chf5ja82AWOyyUJFlYqBD7e7Fy8fff2O8MoOofajC3ZbmiruN4MpmC9ODV/ AZkEzfrkjlY3y+pFhYEEEg34y/oEslLkGTYmiSOib01LEScqxcJv8q43orR6dlo9TfHrqtNurJ/Pm 6EuCNL71Q0+gwc47+/oU4duspzFQj1fUETPkjnEP51RvSRAJiHB7jiZNr5yewQK+gRR411z4rIAM6 Yh+ZMSi7w+uIzuqp1UxyY5r6/B9sHOwczwSUrlV3iupUtu/GkCNBAoiSyvx1WJGH0WaKybmisen/d iJ3YkEpw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wprp3-0000000DLNg-0hqs; Fri, 31 Jul 2026 18:19:05 +0000 Received: from mail-wr1-x430.google.com ([2a00:1450:4864:20::430]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wprp0-0000000DLMS-2KzC for linux-arm-kernel@lists.infradead.org; Fri, 31 Jul 2026 18:19:03 +0000 Received: by mail-wr1-x430.google.com with SMTP id ffacd0b85a97d-47f7027ca11so884993f8f.3 for ; Fri, 31 Jul 2026 11:19:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785521941; x=1786126741; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=6m+8w0QVgGm8urXe/cU07WfU5xAZ+QJVFPsiFH0egMo=; b=myT7WY4BCf6vE+naTBG4p5RQSPVgWgiTAdZ42nE9Pz5wfn99emg5bh6Egeb35jJ2VN dynKTU5Z2V4S2TbtrQK0RMxtKlRpkG65VvtUQWykYA4z2cXJVrYXp8mox40Rpv97FoNv jyahry+N8B9u8JoH5zgIh2MOxOhUSApuYj69K796LzpOFHKwyuDoO3rBNNcz244N8yDk BbwGuaEwM8GSRjsgP/nkd8vFXVEO3dUk0tKPtTL1yZNnGJbrSl8U+QXHm36LSJgsQl44 lKB2lPF2DcnMjN8MXP/Rew7rsUican4Eg39NdiGjAW4DD814mG0roBx0Fb6sXyx6vzo9 jYJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785521941; x=1786126741; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=6m+8w0QVgGm8urXe/cU07WfU5xAZ+QJVFPsiFH0egMo=; b=jR0iXudgaRLVB4hqvw23SMoMb0lxc5oVTrdx4A7LGrVRCcbnKxxGtCT94YE8+K8bzm sIoqdvskWkMmHsg7jpHS0zbVnMiEQcFj1xAqVGVWIklCauXiD52NEiAKkWZKGHInGEdA VoXuu8XgO0e7naPhmeEyJeDiIp6Wf2pMHc9qlMSlEGTMwCSSSo9rtEtR7gOAoWPjjef/ Vcf9Mbh5MWw9xCX2W5oNOcgYOk9+A2s3ZS/YRnX4IqnpTS6kDVfrohQQ47NOl5R9W89/ JnUWSjI90BRyFZGB8ps6L8iqBolwYJZ7CHGLBmtAkBslQ24Uw2wkKqRywd4/sBzQKJgt EliQ== X-Forwarded-Encrypted: i=1; AHgh+RrtQzsBtXGE1Vbfowfv2ppmlJb9adPdYXrjcQuQY78DKMQkuFtfVfSXdPnzBiDZ60uwb13Y8liRMPq6Q1OggvOy@lists.infradead.org X-Gm-Message-State: AOJu0YzAmrwfRru9ighD/qocVOPx3DY0ldRiOKpk7USXYu7UKDdYNVGJ YKH9DLMd1Gx2z8cRZuTq0pHT63AZzvFlHZSYROZpL03SvYjNkmbv5XES X-Gm-Gg: AR+sD10FFE3npX2lDs0AYJd4i4Z683psQxmkaoZqEaGUTxTSAdpIFz7+QkZEc/vUgtL O8kAewdeP7DCkZSNyi7HphJrlHEd5CeiNX4PnV9rh1NmZsUokkbgvY6gbrdKtKY+gEo+JejXgeL 81uJblYC5pCzMWlKlZ8gqGoiYD3BAggaef0VT8YI3srYxcEJgupPCHJ4FAIddIJIP7Mgf24bP3y qWl8ZWgayb4Mr64SavZuhvA7nX3d5++svizc/Pz7WJsBxZiskUlzmYYV58n/DGd+JxXy+tn9uM7 XO+MfXhDtn0OX4j+gV5im/QrA9qFd3InxS570FCOj5mD3yqCOwUpgOWY/RIrZDWp+XN6zAFbZVo HkrRUzLI2AGrqFYAHV42joozIolRAVuX49rQswuL/B5becn72mXnCXmzjsdxPTSdnmq+wvmjF1I Heimws3yuKAVmS0fd0Sp6EsNVmXrr+uXIjsMuDfuRtWFkjryJsx5sYxehSbFjGBSg3YfJ+QqGRY rHyK6TO4BFrgcfJm/eXj2mffX37q9hxRf5YaE2kSsSEtqRW9dHZ4olMiaVnrKsFPk1/A452sO4g Vsc2vs1X0DQxCu1yRnIvIfmoWBVsMbA6alsvGxdp0mCDOKUXUu9tcfDdFTOckoj8Sz+a6XBQCGK Mp9g= X-Received: by 2002:a5d:5002:0:b0:473:823:1924 with SMTP id ffacd0b85a97d-47fd7314b2cmr986964f8f.39.1785521940802; Fri, 31 Jul 2026 11:19:00 -0700 (PDT) Received: from localhost.localdomain (dynamic-2a02-3100-a8d0-bc01-6d31-3d12-3a11-d2d0.310.pool.telefonica.de. [2a02:3100:a8d0:bc01:6d31:3d12:3a11:d2d0]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47fd41d1756sm7293694f8f.4.2026.07.31.11.18.59 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 31 Jul 2026 11:19:00 -0700 (PDT) From: Karl Mehltretter To: Greg Kroah-Hartman , Jiri Slaby Cc: Karl Mehltretter , 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, Sashiko , stable@vger.kernel.org Subject: [PATCH v4 5/5] serial: imx: serialize imx_uart_ports[] lifetime Date: Fri, 31 Jul 2026 20:18:44 +0200 Message-Id: <20260731181844.11330-6-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20260731181844.11330-1-kmehltretter@gmail.com> References: <20260731181844.11330-1-kmehltretter@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260731_111902_621567_9776A79D X-CRM114-Status: GOOD ( 17.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 --- Backport note: the removal fix is self-contained. Complete probe-failure coverage also requires patch 1. With patch 1, all fallible allocations precede console registration, so rollback can safely clear the table. Without it, a late allocation failure (only reachable with fault injection) can leave the console registered after imx_uart_ports[] is cleared, turning the pre-existing use-after-free into a NULL dereference. drivers/tty/serial/imx.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 251a50c8aa38..b0f34a6e7d4f 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -2080,6 +2081,9 @@ static const struct uart_ops imx_uart_pops = { 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) { @@ -2632,11 +2636,19 @@ static int imx_uart_probe(struct platform_device *pdev) } } - 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); @@ -2648,7 +2660,9 @@ static void imx_uart_remove(struct platform_device *pdev) { 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) -- 2.53.0