FAILED: patch "[PATCH] serial: qcom-geni: fix enabling deactivated interrupt" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 5f949f140f73696f64acb89a1f16ff9153d017e0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023052232-girdle-utility-615f@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

5f949f140f73 ("serial: qcom-geni: fix enabling deactivated interrupt") 300894a6fef7 ("serial: qcom_geni_serial: Convert to use resource-managed OPP API")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5f949f140f73696f64acb89a1f16ff9153d017e0 Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <[email protected]>
Date: Fri, 5 May 2023 17:23:01 +0200
Subject: [PATCH] serial: qcom-geni: fix enabling deactivated interrupt

The driver have a race, experienced only with PREEMPT_RT patchset:

CPU0 | CPU1
==================================================================

qcom_geni_serial_probe       |
  uart_add_one_port          |
                             | serdev_drv_probe
                             |   qca_serdev_probe
                             |     serdev_device_open
                             |       uart_open
                             |         uart_startup
                             |           qcom_geni_serial_startup
                             |             enable_irq
                             |               __irq_startup
                             |                 WARN_ON()
                             |                 IRQ not activated
  request_threaded_irq       |
    irq_domain_activate_irq  |

The warning:

894000.serial: ttyHS1 at MMIO 0x894000 (irq = 144, base_baud = 0) is a MSM serial serial0: tty port ttyHS1 registered

  WARNING: CPU: 7 PID: 107 at kernel/irq/chip.c:241 __irq_startup+0x78/0xd8
  ...
  qcom_geni_serial 894000.serial: serial engine reports 0 RX bytes in!

Adding UART port triggers probe of child serial devices - serdev and eventually Qualcomm Bluetooth hci_qca driver. This opens UART port which enables the interrupt before it got activated in request_threaded_irq(). The issue originates in commit f3974413cf02 ("tty: serial: qcom_geni_serial: Wakeup IRQ cleanup") and discussion on mailing list [1]. However the above commit does not explain why the uart_add_one_port() is moved above requesting interrupt.

[1] https://lore.kernel.org/all/[email protected]/

index 08dc3e2a729c..8582479f0211 100644
@@ -1664,19 +1664,18 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	uport->private_data = &port->private_data;
 	platform_set_drvdata(pdev, port);
 
-	ret = uart_add_one_port(drv, uport);
-	if (ret)
-		return ret;
-
 	irq_set_status_flags(uport->irq, IRQ_NOAUTOEN);
 	ret = devm_request_irq(uport->dev, uport->irq, qcom_geni_serial_isr,
 			IRQF_TRIGGER_HIGH, port->name, uport);
 	if (ret) {
 		dev_err(uport->dev, "Failed to get IRQ ret %d\n", ret);
-		uart_remove_one_port(drv, uport);
 		return ret;
 	}
 
+	ret = uart_add_one_port(drv, uport);
+	if (ret)
+		return ret;
+
 	/*
 	 * Set pm_runtime status as ACTIVE so that wakeup_irq gets
 	 * enabled/disabled from dev_pm_arm_wake_irq during system