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Thu, 28 May 2026 16:06:34 -0700 (PDT) Received: from ryzen ([2601:644:8000:5b5d:7285:c2ff:fe45:8a32]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-304ebcc8016sm223109eec.23.2026.05.28.16.06.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 May 2026 16:06:33 -0700 (PDT) From: Rosen Penev To: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman , Jiri Slaby , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , linux-kernel@vger.kernel.org (open list:TTY LAYER AND SERIAL DRIVERS), imx@lists.linux.dev (open list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE), linux-arm-kernel@lists.infradead.org (moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE) Subject: [PATCH] serial: mxs-auart: fix probe error paths and clock handling Date: Thu, 28 May 2026 16:06:16 -0700 Message-ID: <20260528230616.186792-1-rosenp@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: imx@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sashiko reported three pre-existing bugs in the mxs-auart driver: - For non-ASM9260 variants, mxs_get_clks() obtained the clock but never prepared/enabled it, leaving register accesses in probe at risk of faulting if the bootloader had gated the clock. - The error path and remove function used pdev->id instead of s->port.line to clear the auart_port[] slot. For DT-probed devices pdev->id is -1, causing an out-of-bounds write and leaving a dangling pointer in the array. - The probe error path called iounmap() while the IRQ was still registered. An interrupt during that window would dereference the unmapped membase. All of this is a consequence of using mixed devm and non devm. Instead of working around these issues, go full devm so that everything can be cleaned up properly. devm_clk_get_enabled allows removing clk_prepare_enable. devm_platform_get_and_ioremap_resource is a bit worrying as it calls request_mem_region. Manual review of the dts files shows no overlapping memory regions, so should be good to go. Use devm in mxs_auart_request_gpio_irq as devm is used in probe. Assisted-by: Opencode:Big-pickle Signed-off-by: Rosen Penev --- drivers/tty/serial/mxs-auart.c | 110 ++++++--------------------------- 1 file changed, 20 insertions(+), 90 deletions(-) diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 697318dbb146..8b6463df11b3 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -1457,48 +1457,24 @@ static void mxs_init_regs(struct mxs_auart_port *s) static int mxs_get_clks(struct mxs_auart_port *s, struct platform_device *pdev) { - int err; - if (!is_asm9260_auart(s)) { - s->clk = devm_clk_get(&pdev->dev, NULL); + s->clk = devm_clk_get_enabled(&pdev->dev, NULL); return PTR_ERR_OR_ZERO(s->clk); } - s->clk = devm_clk_get(s->dev, "mod"); + s->clk = devm_clk_get_enabled(s->dev, "mod"); if (IS_ERR(s->clk)) { dev_err(s->dev, "Failed to get \"mod\" clk\n"); return PTR_ERR(s->clk); } - s->clk_ahb = devm_clk_get(s->dev, "ahb"); + s->clk_ahb = devm_clk_get_enabled(s->dev, "ahb"); if (IS_ERR(s->clk_ahb)) { dev_err(s->dev, "Failed to get \"ahb\" clk\n"); return PTR_ERR(s->clk_ahb); } - err = clk_prepare_enable(s->clk_ahb); - if (err) { - dev_err(s->dev, "Failed to enable ahb_clk!\n"); - return err; - } - - err = clk_set_rate(s->clk, clk_get_rate(s->clk_ahb)); - if (err) { - dev_err(s->dev, "Failed to set rate!\n"); - goto disable_clk_ahb; - } - - err = clk_prepare_enable(s->clk); - if (err) { - dev_err(s->dev, "Failed to enable clk!\n"); - goto disable_clk_ahb; - } - - return 0; - -disable_clk_ahb: - clk_disable_unprepare(s->clk_ahb); - return err; + return clk_set_rate(s->clk, clk_get_rate(s->clk_ahb)); } static int mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev) @@ -1529,15 +1505,6 @@ static int mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev) return 0; } -static void mxs_auart_free_gpio_irq(struct mxs_auart_port *s) -{ - enum mctrl_gpio_idx i; - - for (i = 0; i < UART_GPIO_MAX; i++) - if (s->gpio_irq[i] >= 0) - free_irq(s->gpio_irq[i], s); -} - static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s) { int *irq = s->gpio_irq; @@ -1549,21 +1516,13 @@ static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s) continue; irq_set_status_flags(irq[i], IRQ_NOAUTOEN); - err = request_irq(irq[i], mxs_auart_irq_handle, - IRQ_TYPE_EDGE_BOTH, dev_name(s->dev), s); + err = devm_request_irq(s->dev, irq[i], mxs_auart_irq_handle, IRQ_TYPE_EDGE_BOTH, + dev_name(s->dev), s); if (err) dev_err(s->dev, "%s - Can't get %d irq\n", __func__, irq[i]); } - /* - * If something went wrong, rollback. - * Be careful: i may be unsigned. - */ - while (err && (i-- > 0)) - if (irq[i] >= 0) - free_irq(irq[i], s); - return err; } @@ -1604,18 +1563,10 @@ static int mxs_auart_probe(struct platform_device *pdev) if (ret) return ret; - r = platform_get_resource(pdev, IORESOURCE_MEM, 0); - if (!r) { - ret = -ENXIO; - goto out_disable_clks; - } - + s->port.membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r); + if (IS_ERR(s->port.membase)) + return PTR_ERR(s->port.membase); s->port.mapbase = r->start; - s->port.membase = ioremap(r->start, resource_size(r)); - if (!s->port.membase) { - ret = -ENOMEM; - goto out_disable_clks; - } s->port.ops = &mxs_auart_ops; s->port.iotype = UPIO_MEM; s->port.fifosize = MXS_AUART_FIFO_SIZE; @@ -1628,23 +1579,20 @@ static int mxs_auart_probe(struct platform_device *pdev) s->mctrl_prev = 0; irq = platform_get_irq(pdev, 0); - if (irq < 0) { - ret = irq; - goto out_iounmap; - } + if (irq < 0) + return irq; s->port.irq = irq; - ret = devm_request_irq(&pdev->dev, irq, mxs_auart_irq_handle, 0, - dev_name(&pdev->dev), s); + ret = devm_request_irq(&pdev->dev, irq, mxs_auart_irq_handle, 0, dev_name(&pdev->dev), s); if (ret) - goto out_iounmap; + return ret; platform_set_drvdata(pdev, s); ret = mxs_auart_init_gpios(s, &pdev->dev); if (ret) { dev_err(&pdev->dev, "Failed to initialize GPIOs.\n"); - goto out_iounmap; + return ret; } /* @@ -1652,15 +1600,17 @@ static int mxs_auart_probe(struct platform_device *pdev) */ ret = mxs_auart_request_gpio_irq(s); if (ret) - goto out_iounmap; + return ret; auart_port[s->port.line] = s; mxs_auart_reset_deassert(s); ret = uart_add_one_port(&auart_driver, &s->port); - if (ret) - goto out_free_qpio_irq; + if (ret) { + auart_port[s->port.line] = NULL; + return ret; + } /* ASM9260 don't have version reg */ if (is_asm9260_auart(s)) { @@ -1673,20 +1623,6 @@ static int mxs_auart_probe(struct platform_device *pdev) } return 0; - -out_free_qpio_irq: - mxs_auart_free_gpio_irq(s); - auart_port[pdev->id] = NULL; - -out_iounmap: - iounmap(s->port.membase); - -out_disable_clks: - if (is_asm9260_auart(s)) { - clk_disable_unprepare(s->clk); - clk_disable_unprepare(s->clk_ahb); - } - return ret; } static void mxs_auart_remove(struct platform_device *pdev) @@ -1694,13 +1630,7 @@ static void mxs_auart_remove(struct platform_device *pdev) struct mxs_auart_port *s = platform_get_drvdata(pdev); uart_remove_one_port(&auart_driver, &s->port); - auart_port[pdev->id] = NULL; - mxs_auart_free_gpio_irq(s); - iounmap(s->port.membase); - if (is_asm9260_auart(s)) { - clk_disable_unprepare(s->clk); - clk_disable_unprepare(s->clk_ahb); - } + auart_port[s->port.line] = NULL; } static struct platform_driver mxs_auart_driver = { -- 2.54.0