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    Subject[PATCH 4.19 165/191] i2c: imx: Fix external abort on interrupt in exit paths
    Date
    From: Krzysztof Kozlowski <krzk@kernel.org>

    commit e50e4f0b85be308a01b830c5fbdffc657e1a6dd0 upstream.

    If interrupt comes late, during probe error path or device remove (could
    be triggered with CONFIG_DEBUG_SHIRQ), the interrupt handler
    i2c_imx_isr() will access registers with the clock being disabled. This
    leads to external abort on non-linefetch on Toradex Colibri VF50 module
    (with Vybrid VF5xx):

    Unhandled fault: external abort on non-linefetch (0x1008) at 0x8882d003
    Internal error: : 1008 [#1] ARM
    Modules linked in:
    CPU: 0 PID: 1 Comm: swapper Not tainted 5.7.0 #607
    Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
    (i2c_imx_isr) from [<8017009c>] (free_irq+0x25c/0x3b0)
    (free_irq) from [<805844ec>] (release_nodes+0x178/0x284)
    (release_nodes) from [<80580030>] (really_probe+0x10c/0x348)
    (really_probe) from [<80580380>] (driver_probe_device+0x60/0x170)
    (driver_probe_device) from [<80580630>] (device_driver_attach+0x58/0x60)
    (device_driver_attach) from [<805806bc>] (__driver_attach+0x84/0xc0)
    (__driver_attach) from [<8057e228>] (bus_for_each_dev+0x68/0xb4)
    (bus_for_each_dev) from [<8057f3ec>] (bus_add_driver+0x144/0x1ec)
    (bus_add_driver) from [<80581320>] (driver_register+0x78/0x110)
    (driver_register) from [<8010213c>] (do_one_initcall+0xa8/0x2f4)
    (do_one_initcall) from [<80c0100c>] (kernel_init_freeable+0x178/0x1dc)
    (kernel_init_freeable) from [<80807048>] (kernel_init+0x8/0x110)
    (kernel_init) from [<80100114>] (ret_from_fork+0x14/0x20)

    Additionally, the i2c_imx_isr() could wake up the wait queue
    (imx_i2c_struct->queue) before its initialization happens.

    The resource-managed framework should not be used for interrupt handling,
    because the resource will be released too late - after disabling clocks.
    The interrupt handler is not prepared for such case.

    Fixes: 1c4b6c3bcf30 ("i2c: imx: implement bus recovery")
    Cc: <stable@vger.kernel.org>
    Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
    Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
    Signed-off-by: Wolfram Sang <wsa@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/i2c/busses/i2c-imx.c | 24 +++++++++++++-----------
    1 file changed, 13 insertions(+), 11 deletions(-)

    --- a/drivers/i2c/busses/i2c-imx.c
    +++ b/drivers/i2c/busses/i2c-imx.c
    @@ -1101,14 +1101,6 @@ static int i2c_imx_probe(struct platform
    return ret;
    }

    - /* Request IRQ */
    - ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, IRQF_SHARED,
    - pdev->name, i2c_imx);
    - if (ret) {
    - dev_err(&pdev->dev, "can't claim irq %d\n", irq);
    - goto clk_disable;
    - }
    -
    /* Init queue */
    init_waitqueue_head(&i2c_imx->queue);

    @@ -1127,6 +1119,14 @@ static int i2c_imx_probe(struct platform
    if (ret < 0)
    goto rpm_disable;

    + /* Request IRQ */
    + ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
    + pdev->name, i2c_imx);
    + if (ret) {
    + dev_err(&pdev->dev, "can't claim irq %d\n", irq);
    + goto rpm_disable;
    + }
    +
    /* Set up clock divider */
    i2c_imx->bitrate = IMX_I2C_BIT_RATE;
    ret = of_property_read_u32(pdev->dev.of_node,
    @@ -1169,13 +1169,12 @@ static int i2c_imx_probe(struct platform

    clk_notifier_unregister:
    clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
    + free_irq(irq, i2c_imx);
    rpm_disable:
    pm_runtime_put_noidle(&pdev->dev);
    pm_runtime_disable(&pdev->dev);
    pm_runtime_set_suspended(&pdev->dev);
    pm_runtime_dont_use_autosuspend(&pdev->dev);
    -
    -clk_disable:
    clk_disable_unprepare(i2c_imx->clk);
    return ret;
    }
    @@ -1183,7 +1182,7 @@ clk_disable:
    static int i2c_imx_remove(struct platform_device *pdev)
    {
    struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
    - int ret;
    + int irq, ret;

    ret = pm_runtime_get_sync(&pdev->dev);
    if (ret < 0)
    @@ -1203,6 +1202,9 @@ static int i2c_imx_remove(struct platfor
    imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);

    clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
    + irq = platform_get_irq(pdev, 0);
    + if (irq >= 0)
    + free_irq(irq, i2c_imx);
    clk_disable_unprepare(i2c_imx->clk);

    pm_runtime_put_noidle(&pdev->dev);

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