rtc: rk808: fix possible race condition
The probe function is not allowed to fail after registering the RTC because the following may happen: CPU0: CPU1: sys_load_module() do_init_module() do_one_initcall() cmos_do_probe() rtc_device_register() __register_chrdev() cdev->owner = struct module* open("/dev/rtc0") rtc_device_unregister() module_put() free_module() module_free(mod->module_core) /* struct module *module is now freed */ chrdev_open() spin_lock(cdev_lock) cdev_get() try_module_get() module_is_live() /* dereferences already freed struct module* */ Switch to devm_rtc_allocate_device/rtc_register_device to register the rtc as late as possible. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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4cda172bc3
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201fac95e7
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@ -405,12 +405,11 @@ static int rk808_rtc_probe(struct platform_device *pdev)
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device_init_wakeup(&pdev->dev, 1);
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device_init_wakeup(&pdev->dev, 1);
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rk808_rtc->rtc = devm_rtc_device_register(&pdev->dev, "rk808-rtc",
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rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
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&rk808_rtc_ops, THIS_MODULE);
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if (IS_ERR(rk808_rtc->rtc))
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if (IS_ERR(rk808_rtc->rtc)) {
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return PTR_ERR(rk808_rtc->rtc);
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ret = PTR_ERR(rk808_rtc->rtc);
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return ret;
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rk808_rtc->rtc->ops = &rk808_rtc_ops;
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}
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rk808_rtc->irq = platform_get_irq(pdev, 0);
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rk808_rtc->irq = platform_get_irq(pdev, 0);
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if (rk808_rtc->irq < 0) {
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if (rk808_rtc->irq < 0) {
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@ -427,9 +426,10 @@ static int rk808_rtc_probe(struct platform_device *pdev)
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if (ret) {
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if (ret) {
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dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
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dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
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rk808_rtc->irq, ret);
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rk808_rtc->irq, ret);
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return ret;
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}
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}
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return ret;
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return rtc_register_device(rk808_rtc->rtc);
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}
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}
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static struct platform_driver rk808_rtc_driver = {
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static struct platform_driver rk808_rtc_driver = {
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