Commit a7cef951 authored Oct 25, 2022 by Biju Das Committed by Lipeng Sang May 23, 2023

can: rcar_canfd: rcar_canfd_handle_global_receive(): fix IRQ storm on global FIFO receive

stable inclusion
from stable-v5.10.153
commit eb69c07eca22ffd8621d9de9378e4b3ce7965190
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=eb69c07eca22ffd8621d9de9378e4b3ce7965190



--------------------------------

commit 702de2c2 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: dd3bd23e ("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.com


Cc: stable@vger.kernel.org
[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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lipeng Sang <sanglipeng1@jd.com>

parent 3ddd5c0f

drivers/net/can/rcar/rcar_canfd.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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,