This is a note to let you know that I've just added the patch titled
can: rcar_canfd: rcar_canfd_handle_global_receive(): fix IRQ storm on global FIFO receive
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
can-rcar_canfd-rcar_canfd_handle_global_receive-fix-irq-storm-on-global-fifo-receive.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 702de2c21eed04c67cefaaedc248ef16e5f6b293 Mon Sep 17 00:00:00 2001
From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Date: Tue, 25 Oct 2022 16:56:55 +0100
Subject: can: rcar_canfd: rcar_canfd_handle_global_receive(): fix IRQ storm on global FIFO receive
From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxx>
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20221025155657.1426948-2-biju.das.jz@xxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
[mkl: adjust commit message]
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/can/rcar/rcar_canfd.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -1157,11 +1157,13 @@ static void rcar_canfd_handle_global_rec
{
struct rcar_canfd_channel *priv = gpriv->ch[ch];
u32 ridx = ch + RCANFD_RFFIFO_IDX;
- u32 sts;
+ u32 sts, cc;
/* Handle Rx interrupts */
sts = rcar_canfd_read(priv->base, RCANFD_RFSTS(gpriv, ridx));
- if (likely(sts & RCANFD_RFSTS_RFIF)) {
+ cc = rcar_canfd_read(priv->base, RCANFD_RFCC(gpriv, 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,
Patches currently in stable-queue which might be from biju.das.jz@xxxxxxxxxxxxxx are
queue-6.0/can-rcar_canfd-fix-channel-specific-irq-handling-for-rz-g2l.patch
queue-6.0/can-rcar_canfd-rcar_canfd_handle_global_receive-fix-irq-storm-on-global-fifo-receive.patch
