On 22.10.2022 09:15:01, Biju Das wrote: > We are seeing IRQ storm on global receive IRQ line under heavy CAN > bus load conditions with both CAN channels are enabled. > > Conditions: > The global receive IRQ line is shared between can0 and can1, either > of the channels can trigger interrupt while the other channel irq > line is disabled(rfie). > When global receive IRQ interrupt occurs, we mask the interrupt in > irqhandler. Clearing and unmasking of the interrupt is happening in > rx_poll(). There is a race condition where rx_poll unmask the > interrupt, but the next irq handler does not mask the irq due to > NAPIF_STATE_MISSED flag. Why does this happen? Is it a problem that you call rcar_canfd_handle_global_receive() for a channel that has the IRQs actually disabled in hardware? > (for eg: can0 rx fifo interrupt enable is > disabled and can1 is triggering rx interrupt, the delay in rx_poll() > processing results in setting NAPIF_STATE_MISSED flag) leading to IRQ > storm. > > This patch fixes the issue by checking irq is masked or not in > irq handler and it masks the interrupt if it is unmasked. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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