On 30/07/2023 23:55, Michał Mirosław wrote: > On Sun, Jul 30, 2023 at 10:30:56PM +0200, Krzysztof Kozlowski wrote: >> On 29/07/2023 18:08, Svyatoslav Ryhel wrote: >>> From: Michał Mirosław <mirq-linux@xxxxxxxxxxxx> >>> >>> Implement driver for hot-plugged I2C busses, where some devices on >>> a bus are hot-pluggable and their presence is indicated by GPIO line. > [...] >>> + priv->irq = platform_get_irq(pdev, 0); >>> + if (priv->irq < 0) >>> + return dev_err_probe(&pdev->dev, priv->irq, >>> + "failed to get IRQ %d\n", priv->irq); >>> + >>> + ret = devm_request_threaded_irq(&pdev->dev, priv->irq, NULL, >>> + i2c_hotplug_interrupt, >>> + IRQF_ONESHOT | IRQF_SHARED, >> >> Shared IRQ with devm is a recipe for disaster. Are you sure this is a >> shared one? You have a remove() function which also points that it is >> not safe. You can: >> 1. investigate to be sure it is 100% safe (please document why do you >> think it is safe) > > Could you elaborate on what is unsafe in using devm with shared > interrupts (as compared to non-shared or not devm-managed)? > > The remove function is indeed reversing the order of cleanup. The > shutdown path can be fixed by removing `remove()` and adding > `devm_add_action_or_reset(...deactivate)` before the IRQ is registered. Shared interrupt might be triggered easily by other device between remove() and irq release function (devm_free_irq() or whatever it is called). Best regards, Krzysztof
