On Sun, Jan 06, 2013 at 09:00:59PM +0100, Julia Lawall wrote: > The function davinci_i2c_remove in drivers/i2c/busses/i2c-davinci.c > contains the following code: > > put_device(&pdev->dev); > > clk_disable_unprepare(dev->clk); > clk_put(dev->clk); > dev->clk = NULL; > > davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0); > free_irq(dev->irq, dev); > > Is there any danger in putting free_irq(dev->irq, dev); after > put_device(&pdev->dev);, because the interrupt handler > i2c_davinci_isr can eg refer to dev->dev. Not having a clock doesn't sound exactly thrilling either when servicing an interrupt. I've seen something like this in the remove path of another driver today as well. I assume a lot of drivers might have such issues. It is also one of the subtle issues with devm_request_irq. The remove path can already render the ISR unusable/oopsable but devm will free the interrupt only after remove has finished. Interrupts need to be properly masked out before. Regards, Wolfram -- Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ |
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