This is a note to let you know that I've just added the patch titled sfc: extend the locking on mcdi->seqno to the 4.19-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: sfc-extend-the-locking-on-mcdi-seqno.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 78e0121ddd154ef576b8e42fbb770fef520329a2 Author: Niels Dossche <dossche.niels@xxxxxxxxx> Date: Tue Mar 1 23:28:22 2022 +0100 sfc: extend the locking on mcdi->seqno [ Upstream commit f1fb205efb0ccca55626fd4ef38570dd16b44719 ] seqno could be read as a stale value outside of the lock. The lock is already acquired to protect the modification of seqno against a possible race condition. Place the reading of this value also inside this locking to protect it against a possible race condition. Signed-off-by: Niels Dossche <dossche.niels@xxxxxxxxx> Acked-by: Martin Habets <habetsm.xilinx@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c index dfad93fca0a6..0fa64b8b79bf 100644 --- a/drivers/net/ethernet/sfc/mcdi.c +++ b/drivers/net/ethernet/sfc/mcdi.c @@ -166,9 +166,9 @@ static void efx_mcdi_send_request(struct efx_nic *efx, unsigned cmd, /* Serialise with efx_mcdi_ev_cpl() and efx_mcdi_ev_death() */ spin_lock_bh(&mcdi->iface_lock); ++mcdi->seqno; + seqno = mcdi->seqno & SEQ_MASK; spin_unlock_bh(&mcdi->iface_lock); - seqno = mcdi->seqno & SEQ_MASK; xflags = 0; if (mcdi->mode == MCDI_MODE_EVENTS) xflags |= MCDI_HEADER_XFLAGS_EVREQ;