From 74eba1c9c6cddf3f954441267a9d5c9665b04603 Mon Sep 17 00:00:00 2001 From: Biju Das Date: Tue, 25 Oct 2022 16:56:55 +0100 Subject: [PATCH] can: rcar_canfd: rcar_canfd_handle_global_receive(): fix IRQ storm on global FIFO receive commit 10dedc50e2f59165ee8be58d68132f2bc659af8e 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: 555bbe510d57 ("can: rcar_canfd: Add Renesas R-Car CAN FD driver") Suggested-by: Marc Kleine-Budde Signed-off-by: Biju Das Link: https://lore.kernel.org/all/20221025155657.1426948-2-biju.das.jz@bp.renesas.com Cc: stable@vger.kernel.org [mkl: adjust commit message] Signed-off-by: Marc Kleine-Budde [biju: removed gpriv from RCANFD_RFCC_RFIE macro] Signed-off-by: Biju Das Signed-off-by: Greg Kroah-Hartman --- 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 d4e9815ca26ff..eed69e7e95ad8 100644 --- a/drivers/net/can/rcar/rcar_canfd.c +++ b/drivers/net/can/rcar/rcar_canfd.c @@ -1075,7 +1075,7 @@ 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 @@ -1093,7 +1093,9 @@ 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, -- 2.39.5