diff options
| author | Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> | 2023-05-05 18:23:01 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-13 14:00:54 +0300 |
| commit | 5f949f140f73696f64acb89a1f16ff9153d017e0 (patch) | |
| tree | 6197878b3eb4aed452ea5c282ab3b3ff9b4a6b9d /drivers/tty | |
| parent | f264f2f6f4788dc031cef60a0cf2881902736709 (diff) | |
| download | linux-5f949f140f73696f64acb89a1f16ff9153d017e0.tar.xz | |
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/5d9f3dfa.1c69fb81.84c4b.30bf@mx.google.com/
Fixes: f3974413cf02 ("tty: serial: qcom_geni_serial: Wakeup IRQ cleanup")
Cc: <stable@vger.kernel.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20230505152301.2181270-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/qcom_geni_serial.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 08dc3e2a729c..8582479f0211 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -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 |