From: Colin Foster <colin.foster@in-advantage.com>
To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc: Jakub Kicinski <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
UNGLinuxDriver@microchip.com,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Claudiu Manoil <claudiu.manoil@nxp.com>,
Vladimir Oltean <vladimir.oltean@nxp.com>,
Vladimir Oltean <olteanv@gmail.com>
Subject: [PATCH v6 net-next 1/5] net: mscc: ocelot: fix mutex lock error during ethtool stats read
Date: Wed, 9 Feb 2022 20:13:41 -0800 [thread overview]
Message-ID: <20220210041345.321216-2-colin.foster@in-advantage.com> (raw)
In-Reply-To: <20220210041345.321216-1-colin.foster@in-advantage.com>
An ongoing workqueue populates the stats buffer. At the same time, a user
might query the statistics. While writing to the buffer is mutex-locked,
reading from the buffer wasn't. This could lead to buggy reads by ethtool.
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Fixes: a556c76adc052 ("net: mscc: Add initial Ocelot switch support")
Reported-by: Vladimir Oltean <olteanv@gmail.com>
---
drivers/net/ethernet/mscc/ocelot.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 455293aa6343..6933dff1dd37 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1737,12 +1737,11 @@ void ocelot_get_strings(struct ocelot *ocelot, int port, u32 sset, u8 *data)
}
EXPORT_SYMBOL(ocelot_get_strings);
+/* Caller must hold &ocelot->stats_lock */
static void ocelot_update_stats(struct ocelot *ocelot)
{
int i, j;
- mutex_lock(&ocelot->stats_lock);
-
for (i = 0; i < ocelot->num_phys_ports; i++) {
/* Configure the port to read the stats from */
ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(i), SYS_STAT_CFG);
@@ -1761,8 +1760,6 @@ static void ocelot_update_stats(struct ocelot *ocelot)
~(u64)U32_MAX) + val;
}
}
-
- mutex_unlock(&ocelot->stats_lock);
}
static void ocelot_check_stats_work(struct work_struct *work)
@@ -1771,7 +1768,9 @@ static void ocelot_check_stats_work(struct work_struct *work)
struct ocelot *ocelot = container_of(del_work, struct ocelot,
stats_work);
+ mutex_lock(&ocelot->stats_lock);
ocelot_update_stats(ocelot);
+ mutex_unlock(&ocelot->stats_lock);
queue_delayed_work(ocelot->stats_queue, &ocelot->stats_work,
OCELOT_STATS_CHECK_DELAY);
@@ -1781,12 +1780,16 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data)
{
int i;
+ mutex_lock(&ocelot->stats_lock);
+
/* check and update now */
ocelot_update_stats(ocelot);
/* Copy all counters */
for (i = 0; i < ocelot->num_stats; i++)
*data++ = ocelot->stats[port * ocelot->num_stats + i];
+
+ mutex_unlock(&ocelot->stats_lock);
}
EXPORT_SYMBOL(ocelot_get_ethtool_stats);
--
2.25.1
next prev parent reply other threads:[~2022-02-10 4:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-10 4:13 [PATCH v6 net-next 0/5] use bulk reads for ocelot statistics Colin Foster
2022-02-10 4:13 ` Colin Foster [this message]
2022-02-10 9:50 ` [PATCH v6 net-next 1/5] net: mscc: ocelot: fix mutex lock error during ethtool stats read Vladimir Oltean
2022-02-10 4:13 ` [PATCH v6 net-next 2/5] net: mscc: ocelot: remove unnecessary stat reading from ethtool Colin Foster
2022-02-10 10:34 ` Vladimir Oltean
2022-02-10 4:13 ` [PATCH v6 net-next 3/5] net: ocelot: align macros for consistency Colin Foster
2022-02-10 4:13 ` [PATCH v6 net-next 4/5] net: mscc: ocelot: add ability to perform bulk reads Colin Foster
2022-02-10 4:13 ` [PATCH v6 net-next 5/5] net: mscc: ocelot: use bulk reads for stats Colin Foster
2022-02-10 10:36 ` Vladimir Oltean
2022-02-10 14:37 ` Colin Foster
2022-02-10 15:21 ` Colin Foster
2022-02-10 15:27 ` Vladimir Oltean
2022-02-10 15:35 ` Colin Foster
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