| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20251025171314.1939608-3-mmyangfl@gmail.com>
Date: Sun, 26 Oct 2025 01:13:11 +0800
From: David Yang <mmyangfl@...il.com>
To: netdev@...r.kernel.org
Cc: David Yang <mmyangfl@...il.com>,
Andrew Lunn <andrew@...n.ch>,
Vladimir Oltean <olteanv@...il.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH net-next v2 2/2] net: dsa: yt921x: Protect MIB stats with a lock
64bit variables might not be atomic on 32bit architectures, thus cannot
be made lock-free. Protect them with a spin lock since get_stats64()
cannot sleep.
Signed-off-by: David Yang <mmyangfl@...il.com>
---
drivers/net/dsa/yt921x.c | 63 ++++++++++++++++++++++++++--------------
drivers/net/dsa/yt921x.h | 4 +++
2 files changed, 45 insertions(+), 22 deletions(-)
diff --git a/drivers/net/dsa/yt921x.c b/drivers/net/dsa/yt921x.c
index 97a7eeb4ea15..e5d7c6820089 100644
--- a/drivers/net/dsa/yt921x.c
+++ b/drivers/net/dsa/yt921x.c
@@ -671,22 +671,16 @@ yt921x_mbus_ext_init(struct yt921x_priv *priv, struct device_node *mnp)
static int yt921x_read_mib(struct yt921x_priv *priv, int port)
{
struct yt921x_port *pp = &priv->ports[port];
+ struct yt921x_mib *mib_new = &pp->mib_new;
struct device *dev = to_device(priv);
struct yt921x_mib *mib = &pp->mib;
+ u64 rx_frames;
+ u64 tx_frames;
int res = 0;
- /* Reading of yt921x_port::mib is not protected by a lock and it's vain
- * to keep its consistency, since we have to read registers one by one
- * and there is no way to make a snapshot of MIB stats.
- *
- * Writing (by this function only) is and should be protected by
- * reg_lock.
- */
-
for (size_t i = 0; i < ARRAY_SIZE(yt921x_mib_descs); i++) {
const struct yt921x_mib_desc *desc = &yt921x_mib_descs[i];
u32 reg = YT921X_MIBn_DATA0(port) + desc->offset;
- u64 *valp = &((u64 *)mib)[i];
u64 val;
u32 val0;
@@ -695,7 +689,7 @@ static int yt921x_read_mib(struct yt921x_priv *priv, int port)
break;
if (desc->size <= 1) {
- u64 old_val = *valp;
+ u64 old_val = ((u64 *)mib)[i];
val = (old_val & ~(u64)U32_MAX) | val0;
if (val < old_val)
@@ -709,22 +703,31 @@ static int yt921x_read_mib(struct yt921x_priv *priv, int port)
val = ((u64)val0 << 32) | val1;
}
- WRITE_ONCE(*valp, val);
+ ((u64 *)mib_new)[i] = val;
}
- pp->rx_frames = mib->rx_64byte + mib->rx_65_127byte +
- mib->rx_128_255byte + mib->rx_256_511byte +
- mib->rx_512_1023byte + mib->rx_1024_1518byte +
- mib->rx_jumbo;
- pp->tx_frames = mib->tx_64byte + mib->tx_65_127byte +
- mib->tx_128_255byte + mib->tx_256_511byte +
- mib->tx_512_1023byte + mib->tx_1024_1518byte +
- mib->tx_jumbo;
-
- if (res)
+ if (res) {
dev_err(dev, "Failed to %s port %d: %i\n", "read stats for",
port, res);
- return res;
+ return res;
+ }
+
+ rx_frames = mib->rx_64byte + mib->rx_65_127byte +
+ mib->rx_128_255byte + mib->rx_256_511byte +
+ mib->rx_512_1023byte + mib->rx_1024_1518byte +
+ mib->rx_jumbo;
+ tx_frames = mib->tx_64byte + mib->tx_65_127byte +
+ mib->tx_128_255byte + mib->tx_256_511byte +
+ mib->tx_512_1023byte + mib->tx_1024_1518byte +
+ mib->tx_jumbo;
+
+ spin_lock(&pp->stats_lock);
+ *mib = *mib_new;
+ pp->rx_frames = rx_frames;
+ pp->tx_frames = tx_frames;
+ spin_unlock(&pp->stats_lock);
+
+ return 0;
}
static void yt921x_poll_mib(struct work_struct *work)
@@ -773,6 +776,7 @@ yt921x_dsa_get_ethtool_stats(struct dsa_switch *ds, int port, uint64_t *data)
yt921x_read_mib(priv, port);
mutex_unlock(&priv->reg_lock);
+ spin_lock(&pp->stats_lock);
j = 0;
for (size_t i = 0; i < ARRAY_SIZE(yt921x_mib_descs); i++) {
const struct yt921x_mib_desc *desc = &yt921x_mib_descs[i];
@@ -783,6 +787,7 @@ yt921x_dsa_get_ethtool_stats(struct dsa_switch *ds, int port, uint64_t *data)
data[j] = ((u64 *)mib)[i];
j++;
}
+ spin_unlock(&pp->stats_lock);
}
static int yt921x_dsa_get_sset_count(struct dsa_switch *ds, int port, int sset)
@@ -814,6 +819,7 @@ yt921x_dsa_get_eth_mac_stats(struct dsa_switch *ds, int port,
yt921x_read_mib(priv, port);
mutex_unlock(&priv->reg_lock);
+ spin_lock(&pp->stats_lock);
mac_stats->FramesTransmittedOK = pp->tx_frames;
mac_stats->SingleCollisionFrames = mib->tx_single_collisions;
mac_stats->MultipleCollisionFrames = mib->tx_multiple_collisions;
@@ -836,6 +842,7 @@ yt921x_dsa_get_eth_mac_stats(struct dsa_switch *ds, int port,
/* mac_stats->InRangeLengthErrors */
/* mac_stats->OutOfRangeLengthField */
mac_stats->FrameTooLongErrors = mib->rx_oversize_errors;
+ spin_unlock(&pp->stats_lock);
}
static void
@@ -850,9 +857,11 @@ yt921x_dsa_get_eth_ctrl_stats(struct dsa_switch *ds, int port,
yt921x_read_mib(priv, port);
mutex_unlock(&priv->reg_lock);
+ spin_lock(&pp->stats_lock);
ctrl_stats->MACControlFramesTransmitted = mib->tx_pause;
ctrl_stats->MACControlFramesReceived = mib->rx_pause;
/* ctrl_stats->UnsupportedOpcodesReceived */
+ spin_unlock(&pp->stats_lock);
}
static const struct ethtool_rmon_hist_range yt921x_rmon_ranges[] = {
@@ -881,6 +890,8 @@ yt921x_dsa_get_rmon_stats(struct dsa_switch *ds, int port,
*ranges = yt921x_rmon_ranges;
+ spin_lock(&pp->stats_lock);
+
rmon_stats->undersize_pkts = mib->rx_undersize_errors;
rmon_stats->oversize_pkts = mib->rx_oversize_errors;
rmon_stats->fragments = mib->rx_alignment_errors;
@@ -901,6 +912,8 @@ yt921x_dsa_get_rmon_stats(struct dsa_switch *ds, int port,
rmon_stats->hist_tx[4] = mib->tx_512_1023byte;
rmon_stats->hist_tx[5] = mib->tx_1024_1518byte;
rmon_stats->hist_tx[6] = mib->tx_jumbo;
+
+ spin_unlock(&pp->stats_lock);
}
static void
@@ -911,6 +924,8 @@ yt921x_dsa_get_stats64(struct dsa_switch *ds, int port,
struct yt921x_port *pp = &priv->ports[port];
struct yt921x_mib *mib = &pp->mib;
+ spin_lock(&pp->stats_lock);
+
stats->rx_length_errors = mib->rx_undersize_errors +
mib->rx_fragment_errors;
stats->rx_over_errors = mib->rx_oversize_errors;
@@ -937,6 +952,8 @@ yt921x_dsa_get_stats64(struct dsa_switch *ds, int port,
/* stats->tx_dropped */
stats->multicast = mib->rx_multicast;
stats->collisions = mib->tx_collisions;
+
+ spin_unlock(&pp->stats_lock);
}
static void
@@ -951,8 +968,10 @@ yt921x_dsa_get_pause_stats(struct dsa_switch *ds, int port,
yt921x_read_mib(priv, port);
mutex_unlock(&priv->reg_lock);
+ spin_lock(&pp->stats_lock);
pause_stats->tx_pause_frames = mib->tx_pause;
pause_stats->rx_pause_frames = mib->rx_pause;
+ spin_unlock(&pp->stats_lock);
}
static int
diff --git a/drivers/net/dsa/yt921x.h b/drivers/net/dsa/yt921x.h
index 3e85d90826fb..be69c3508da8 100644
--- a/drivers/net/dsa/yt921x.h
+++ b/drivers/net/dsa/yt921x.h
@@ -470,9 +470,13 @@ struct yt921x_port {
bool isolated;
struct delayed_work mib_read;
+ spinlock_t stats_lock;
struct yt921x_mib mib;
u64 rx_frames;
u64 tx_frames;
+
+ /* only used by read routine to avoid huge allocations on the stack */
+ struct yt921x_mib mib_new;
};
struct yt921x_reg_ops {
--
2.51.0
Powered by blists - more mailing lists