From: Niels Dossche <dossche.niels@gmail.com>
To: netdev@vger.kernel.org
Cc: Edward Cree <ecree.xilinx@gmail.com>,
Martin Habets <habetsm.xilinx@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Niels Dossche <dossche.niels@gmail.com>
Subject: [PATCH] sfc: extend the locking on mcdi->seqno
Date: Tue, 1 Mar 2022 23:28:22 +0100 [thread overview]
Message-ID: <20220301222822.19241-1-dossche.niels@gmail.com> (raw)
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@gmail.com>
---
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 be6bfd6b7ec7..50baf62b2cbc 100644
--- a/drivers/net/ethernet/sfc/mcdi.c
+++ b/drivers/net/ethernet/sfc/mcdi.c
@@ -163,9 +163,9 @@ 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;
--
2.35.1
next reply other threads:[~2022-03-01 22:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-01 22:28 Niels Dossche [this message]
2022-03-03 8:12 ` [PATCH] sfc: extend the locking on mcdi->seqno Martin Habets
2022-03-03 14:20 ` patchwork-bot+netdevbpf
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