commit 702de2c21eed04c67cefaaedc248ef16e5f6b293 upstream.

We are seeing an IRQ storm on the global receive IRQ line under heavy CAN bus load conditions with both CAN channels enabled.

Conditions:

The global receive IRQ line is shared between can0 and can1, either of the channels can trigger interrupt while the other channel's IRQ line is disabled (RFIE).

When global a receive IRQ interrupt occurs, we mask the interrupt in the IRQ handler. Clearing and unmasking of the interrupt is happening in rx_poll(). There is a race condition where rx_poll() unmasks the interrupt, but the next IRQ handler does not mask the IRQ due to NAPIF_STATE_MISSED flag (e.g.: can0 RX FIFO interrupt is disabled and can1 is triggering RX interrupt, the delay in rx_poll() processing results in setting NAPIF_STATE_MISSED flag) leading to an IRQ storm.

This patch fixes the issue by checking IRQ active and enabled before handling the IRQ on a particular channel.

Fixes: dd3bd23eb438 ("can: rcar_canfd: Add Renesas R-Car CAN FD driver") Suggested-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Biju Das biju.das.jz@bp.renesas.com Link: https://lore.kernel.org/all/20221025155657.1426948-2-biju.das.jz@bp.renesas.... Cc: stable@vger.kernel.org # 4.14.y [mkl: adjust commit message] Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de [biju: removed gpriv from RCANFD_RFCC_RFIE macro] Signed-off-by: Biju Das biju.das.jz@bp.renesas.com --- Resending to 4.14 with confilcts[1] fixed [1] https://lore.kernel.org/stable/1667194208232105@kroah.com/T/#u --- drivers/net/can/rcar/rcar_canfd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c index a1634834b640..cb1388267fe0 100644 --- a/drivers/net/can/rcar/rcar_canfd.c +++ b/drivers/net/can/rcar/rcar_canfd.c @@ -1079,7 +1079,7 @@ static irqreturn_t rcar_canfd_global_interrupt(int irq, void *dev_id) struct rcar_canfd_global *gpriv = dev_id; struct net_device *ndev; struct rcar_canfd_channel *priv; - u32 sts, gerfl; + u32 sts, cc, gerfl; u32 ch, ridx;

/* Global error interrupts still indicate a condition specific @@ -1097,7 +1097,9 @@ static irqreturn_t rcar_canfd_global_interrupt(int irq, void *dev_id)

/* Handle Rx interrupts */ sts = rcar_canfd_read(priv->base, RCANFD_RFSTS(ridx)); - if (likely(sts & RCANFD_RFSTS_RFIF)) { + cc = rcar_canfd_read(priv->base, RCANFD_RFCC(ridx)); + if (likely(sts & RCANFD_RFSTS_RFIF && + cc & RCANFD_RFCC_RFIE)) { if (napi_schedule_prep(&priv->napi)) { /* Disable Rx FIFO interrupts */ rcar_canfd_clear_bit(priv->base,