On Mon, Oct 31, 2022 at 09:04:20AM +0000, Biju Das wrote:
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 # 4.9.x [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 4.9 with confilcts[1] fixed [1] https://lore.kernel.org/stable/OS0PR01MB59226F2443DFCE7C5D73778786379@OS0PR0...
drivers/net/can/rcar/rcar_canfd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
All now queued up, thanks.
greg k-h