[PATCH AUTOSEL 5.4 1/2] can: statistics: use atomic access in hot path

[PATCH AUTOSEL 5.4 1/2] can: statistics: use atomic access in hot path

[Sasha Levin]

From: Oliver Hartkopp <socketcan@hartkopp.net>

[ Upstream commit 80b5f90158d1364cbd80ad82852a757fc0692bf2 ]

In can_send() and can_receive() CAN messages and CAN filter matches are
counted to be visible in the CAN procfs files.

KCSAN detected a data race within can_send() when two CAN frames have
been generated by a timer event writing to the same CAN netdevice at the
same time. Use atomic operations to access the statistics in the hot path
to fix the KCSAN complaint.

Reported-by: syzbot+78ce4489b812515d5e4d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67cd717d.050a0220.e1a89.0006.GAE@google.com
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://patch.msgid.link/20250310143353.3242-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/can/af_can.c | 12 ++++++------
 net/can/af_can.h | 12 ++++++------
 net/can/proc.c   | 46 +++++++++++++++++++++++++++-------------------
 3 files changed, 39 insertions(+), 31 deletions(-)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index bc06016a4fe90..d2fd12da30c60 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -288,8 +288,8 @@ int can_send(struct sk_buff *skb, int loop)
 		netif_rx_ni(newskb);
 
 	/* update statistics */
-	pkg_stats->tx_frames++;
-	pkg_stats->tx_frames_delta++;
+	atomic_long_inc(&pkg_stats->tx_frames);
+	atomic_long_inc(&pkg_stats->tx_frames_delta);
 
 	return 0;
 
@@ -647,8 +647,8 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev)
 	int matches;
 
 	/* update statistics */
-	pkg_stats->rx_frames++;
-	pkg_stats->rx_frames_delta++;
+	atomic_long_inc(&pkg_stats->rx_frames);
+	atomic_long_inc(&pkg_stats->rx_frames_delta);
 
 	/* create non-zero unique skb identifier together with *skb */
 	while (!(can_skb_prv(skb)->skbcnt))
@@ -669,8 +669,8 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev)
 	consume_skb(skb);
 
 	if (matches > 0) {
-		pkg_stats->matches++;
-		pkg_stats->matches_delta++;
+		atomic_long_inc(&pkg_stats->matches);
+		atomic_long_inc(&pkg_stats->matches_delta);
 	}
 }
 
diff --git a/net/can/af_can.h b/net/can/af_can.h
index 7c2d9161e2245..22f3352c77fec 100644
--- a/net/can/af_can.h
+++ b/net/can/af_can.h
@@ -66,9 +66,9 @@ struct receiver {
 struct can_pkg_stats {
 	unsigned long jiffies_init;
 
-	unsigned long rx_frames;
-	unsigned long tx_frames;
-	unsigned long matches;
+	atomic_long_t rx_frames;
+	atomic_long_t tx_frames;
+	atomic_long_t matches;
 
 	unsigned long total_rx_rate;
 	unsigned long total_tx_rate;
@@ -82,9 +82,9 @@ struct can_pkg_stats {
 	unsigned long max_tx_rate;
 	unsigned long max_rx_match_ratio;
 
-	unsigned long rx_frames_delta;
-	unsigned long tx_frames_delta;
-	unsigned long matches_delta;
+	atomic_long_t rx_frames_delta;
+	atomic_long_t tx_frames_delta;
+	atomic_long_t matches_delta;
 };
 
 /* persistent statistics */
diff --git a/net/can/proc.c b/net/can/proc.c
index a5fc63c78370e..ea442ddd4fd9d 100644
--- a/net/can/proc.c
+++ b/net/can/proc.c
@@ -123,6 +123,13 @@ void can_stat_update(struct timer_list *t)
 	struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
 	unsigned long j = jiffies; /* snapshot */
 
+	long rx_frames = atomic_long_read(&pkg_stats->rx_frames);
+	long tx_frames = atomic_long_read(&pkg_stats->tx_frames);
+	long matches = atomic_long_read(&pkg_stats->matches);
+	long rx_frames_delta = atomic_long_read(&pkg_stats->rx_frames_delta);
+	long tx_frames_delta = atomic_long_read(&pkg_stats->tx_frames_delta);
+	long matches_delta = atomic_long_read(&pkg_stats->matches_delta);
+
 	/* restart counting in timer context on user request */
 	if (user_reset)
 		can_init_stats(net);
@@ -132,35 +139,33 @@ void can_stat_update(struct timer_list *t)
 		can_init_stats(net);
 
 	/* prevent overflow in calc_rate() */
-	if (pkg_stats->rx_frames > (ULONG_MAX / HZ))
+	if (rx_frames > (LONG_MAX / HZ))
 		can_init_stats(net);
 
 	/* prevent overflow in calc_rate() */
-	if (pkg_stats->tx_frames > (ULONG_MAX / HZ))
+	if (tx_frames > (LONG_MAX / HZ))
 		can_init_stats(net);
 
 	/* matches overflow - very improbable */
-	if (pkg_stats->matches > (ULONG_MAX / 100))
+	if (matches > (LONG_MAX / 100))
 		can_init_stats(net);
 
 	/* calc total values */
-	if (pkg_stats->rx_frames)
-		pkg_stats->total_rx_match_ratio = (pkg_stats->matches * 100) /
-			pkg_stats->rx_frames;
+	if (rx_frames)
+		pkg_stats->total_rx_match_ratio = (matches * 100) / rx_frames;
 
 	pkg_stats->total_tx_rate = calc_rate(pkg_stats->jiffies_init, j,
-					    pkg_stats->tx_frames);
+					    tx_frames);
 	pkg_stats->total_rx_rate = calc_rate(pkg_stats->jiffies_init, j,
-					    pkg_stats->rx_frames);
+					    rx_frames);
 
 	/* calc current values */
-	if (pkg_stats->rx_frames_delta)
+	if (rx_frames_delta)
 		pkg_stats->current_rx_match_ratio =
-			(pkg_stats->matches_delta * 100) /
-			pkg_stats->rx_frames_delta;
+			(matches_delta * 100) /	rx_frames_delta;
 
-	pkg_stats->current_tx_rate = calc_rate(0, HZ, pkg_stats->tx_frames_delta);
-	pkg_stats->current_rx_rate = calc_rate(0, HZ, pkg_stats->rx_frames_delta);
+	pkg_stats->current_tx_rate = calc_rate(0, HZ, tx_frames_delta);
+	pkg_stats->current_rx_rate = calc_rate(0, HZ, rx_frames_delta);
 
 	/* check / update maximum values */
 	if (pkg_stats->max_tx_rate < pkg_stats->current_tx_rate)
@@ -173,9 +178,9 @@ void can_stat_update(struct timer_list *t)
 		pkg_stats->max_rx_match_ratio = pkg_stats->current_rx_match_ratio;
 
 	/* clear values for 'current rate' calculation */
-	pkg_stats->tx_frames_delta = 0;
-	pkg_stats->rx_frames_delta = 0;
-	pkg_stats->matches_delta   = 0;
+	atomic_long_set(&pkg_stats->tx_frames_delta, 0);
+	atomic_long_set(&pkg_stats->rx_frames_delta, 0);
+	atomic_long_set(&pkg_stats->matches_delta, 0);
 
 	/* restart timer (one second) */
 	mod_timer(&net->can.stattimer, round_jiffies(jiffies + HZ));
@@ -217,9 +222,12 @@ static int can_stats_proc_show(struct seq_file *m, void *v)
 	struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
 
 	seq_putc(m, '\n');
-	seq_printf(m, " %8ld transmitted frames (TXF)\n", pkg_stats->tx_frames);
-	seq_printf(m, " %8ld received frames (RXF)\n", pkg_stats->rx_frames);
-	seq_printf(m, " %8ld matched frames (RXMF)\n", pkg_stats->matches);
+	seq_printf(m, " %8ld transmitted frames (TXF)\n",
+		   atomic_long_read(&pkg_stats->tx_frames));
+	seq_printf(m, " %8ld received frames (RXF)\n",
+		   atomic_long_read(&pkg_stats->rx_frames));
+	seq_printf(m, " %8ld matched frames (RXMF)\n",
+		   atomic_long_read(&pkg_stats->matches));
 
 	seq_putc(m, '\n');
 
-- 
2.39.5

[PATCH AUTOSEL 5.4 2/2] hwmon: (nct6775-core) Fix out of bounds access for NCT679{8,9}

[Sasha Levin]

From: Tasos Sahanidis <tasos@tasossah.com>

[ Upstream commit 815f80ad20b63830949a77c816e35395d5d55144 ]

pwm_num is set to 7 for these chips, but NCT6776_REG_PWM_MODE and
NCT6776_PWM_MODE_MASK only contain 6 values.

Fix this by adding another 0 to the end of each array.

Signed-off-by: Tasos Sahanidis <tasos@tasossah.com>
Link: https://lore.kernel.org/r/20250312030832.106475-1-tasos@tasossah.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/hwmon/nct6775.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/nct6775.c b/drivers/hwmon/nct6775.c
index da6bbfca15fee..a6b7919ab63fe 100644
--- a/drivers/hwmon/nct6775.c
+++ b/drivers/hwmon/nct6775.c
@@ -420,8 +420,8 @@ static const s8 NCT6776_BEEP_BITS[] = {
 static const u16 NCT6776_REG_TOLERANCE_H[] = {
 	0x10c, 0x20c, 0x30c, 0x80c, 0x90c, 0xa0c, 0xb0c };
 
-static const u8 NCT6776_REG_PWM_MODE[] = { 0x04, 0, 0, 0, 0, 0 };
-static const u8 NCT6776_PWM_MODE_MASK[] = { 0x01, 0, 0, 0, 0, 0 };
+static const u8 NCT6776_REG_PWM_MODE[] = { 0x04, 0, 0, 0, 0, 0, 0 };
+static const u8 NCT6776_PWM_MODE_MASK[] = { 0x01, 0, 0, 0, 0, 0, 0 };
 
 static const u16 NCT6776_REG_FAN_MIN[] = {
 	0x63a, 0x63c, 0x63e, 0x640, 0x642, 0x64a, 0x64c };
-- 
2.39.5