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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jacob Keller <jacob.e.keller@intel.com>,
        Gurucharan G <gurucharanx.g@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.14 275/334] ice: add lock around Tx timestamp tracker flush
Date:   Mon, 13 Sep 2021 15:15:29 +0200
Message-Id: <20210913131122.723500884@linuxfoundation.org>
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From: Jacob Keller <jacob.e.keller@intel.com>

[ Upstream commit 4dd0d5c33c3ebf24a07cae6141648aeb7ba56072 ]

The driver didn't take the lock while flushing the Tx tracker, which
could cause a race where one thread is trying to read timestamps out
while another thread is trying to read the tracker to check the
timestamps.

Avoid this by ensuring that flushing is locked against read accesses.

Fixes: ea9b847cda64 ("ice: enable transmit timestamps for E810 devices")
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ice/ice_ptp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
index f54148fb0e21..8970037177fe 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
@@ -1278,6 +1278,8 @@ ice_ptp_flush_tx_tracker(struct ice_pf *pf, struct ice_ptp_tx *tx)
 {
 	u8 idx;
 
+	spin_lock(&tx->lock);
+
 	for (idx = 0; idx < tx->len; idx++) {
 		u8 phy_idx = idx + tx->quad_offset;
 
@@ -1290,6 +1292,8 @@ ice_ptp_flush_tx_tracker(struct ice_pf *pf, struct ice_ptp_tx *tx)
 			tx->tstamps[idx].skb = NULL;
 		}
 	}
+
+	spin_unlock(&tx->lock);
 }
 
 /**
-- 
2.30.2