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Message-Id: <20220321133216.925997549@linuxfoundation.org>
Date: Mon, 21 Mar 2022 14:51:39 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Niels Dossche <dossche.niels@...il.com>,
Martin Habets <habetsm.xilinx@...il.com>,
"David S. Miller" <davem@...emloft.net>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 09/16] sfc: extend the locking on mcdi->seqno
From: Niels Dossche <dossche.niels@...il.com>
[ 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@...il.com>
Acked-by: Martin Habets <habetsm.xilinx@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/net/ethernet/sfc/mcdi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c
index 241520943ada..221798499e24 100644
--- a/drivers/net/ethernet/sfc/mcdi.c
+++ b/drivers/net/ethernet/sfc/mcdi.c
@@ -162,9 +162,9 @@ 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;
--
2.34.1
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