* [PATCH 6.18.y 2/3] hwmon: chipcap2: serialize access to the alarm indicators
2026-11-12 5:13 ` [PATCH 6.18.y 1/3] hwmon: (chipcap2) Drop unnecessary include files Sasha Levin
@ 2026-11-12 5:13 ` Sasha Levin
2026-11-12 5:13 ` [PATCH 6.18.y 3/3] hwmon: chipcap2: synchronize ready IRQ state Sasha Levin
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2026-11-12 5:13 UTC (permalink / raw)
To: stable; +Cc: Javier Carrasco, Guenter Roeck, Sasha Levin
From: Javier Carrasco <javier.carrasco.cruz@gmail.com>
[ Upstream commit bed5f0c075eb99442fca6a61c009a32752eceda2 ]
low_alarm and high_alarm are accessed from the threaded interrupt
handlers and from sysfs without any locking, which can lead to lost
alarms.
Add a mutex to serialize the access to the alarm indicators and to
process_irqs, which the handlers use to decide whether an interrupt
belongs to an ongoing operation.
Fixes: 3af350929e75 ("hwmon: Add support for Amphenol ChipCap 2")
Cc: stable@vger.kernel.org
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20261014-chipcap2_locks-v3-10-27ebfc2c5b9e@gmail.com
[groeck: Dropped obsolete 'Assisted-by: tag]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Stable-dep-of: 8c02722be2ca ("hwmon: chipcap2: synchronize ready IRQ state")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/chipcap2.c | 58 +++++++++++++++++++++++++---------------
1 file changed, 37 insertions(+), 21 deletions(-)
diff --git a/drivers/hwmon/chipcap2.c b/drivers/hwmon/chipcap2.c
index a3d5d99bd57ea..49df66728ae9d 100644
--- a/drivers/hwmon/chipcap2.c
+++ b/drivers/hwmon/chipcap2.c
@@ -20,6 +20,7 @@
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
+#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/unaligned.h>
#include <linux/regulator/consumer.h>
@@ -88,6 +89,8 @@ struct cc2_data {
int irq_low;
int irq_high;
bool process_irqs;
+ /* protects process_irqs and the alarm indicators */
+ struct mutex irq_lock;
bool regulator_enabled;
};
@@ -119,7 +122,8 @@ static int cc2_enable(struct cc2_data *data)
/* exclusive regulator, check in case a disable failed */
if (data->regulator_enabled) {
- data->process_irqs = true;
+ scoped_guard(mutex, &data->irq_lock)
+ data->process_irqs = true;
return 0;
}
@@ -134,7 +138,8 @@ static int cc2_enable(struct cc2_data *data)
usleep_range(CC2_STARTUP_TIME_US, CC2_STARTUP_TIME_US + 125);
- data->process_irqs = true;
+ scoped_guard(mutex, &data->irq_lock)
+ data->process_irqs = true;
return 0;
}
@@ -151,7 +156,8 @@ static void cc2_disable(struct cc2_data *data)
synchronize_irq(data->irq_high);
/* ignore alarms triggered by voltage toggling when powering up */
- data->process_irqs = false;
+ scoped_guard(mutex, &data->irq_lock)
+ data->process_irqs = false;
/* exclusive regulator, check in case an enable failed */
if (!data->regulator_enabled)
@@ -502,10 +508,12 @@ static irqreturn_t cc2_low_interrupt(int irq, void *data)
{
struct cc2_data *cc2 = data;
- if (cc2->process_irqs) {
- hwmon_notify_event(cc2->hwmon, hwmon_humidity,
- hwmon_humidity_min_alarm, 0);
- cc2->rh_alarm.low_alarm = true;
+ scoped_guard(mutex, &cc2->irq_lock) {
+ if (cc2->process_irqs) {
+ hwmon_notify_event(cc2->hwmon, hwmon_humidity,
+ hwmon_humidity_min_alarm, 0);
+ cc2->rh_alarm.low_alarm = true;
+ }
}
return IRQ_HANDLED;
@@ -515,10 +523,12 @@ static irqreturn_t cc2_high_interrupt(int irq, void *data)
{
struct cc2_data *cc2 = data;
- if (cc2->process_irqs) {
- hwmon_notify_event(cc2->hwmon, hwmon_humidity,
- hwmon_humidity_max_alarm, 0);
- cc2->rh_alarm.high_alarm = true;
+ scoped_guard(mutex, &cc2->irq_lock) {
+ if (cc2->process_irqs) {
+ hwmon_notify_event(cc2->hwmon, hwmon_humidity,
+ hwmon_humidity_max_alarm, 0);
+ cc2->rh_alarm.high_alarm = true;
+ }
}
return IRQ_HANDLED;
@@ -534,11 +544,13 @@ static int cc2_humidity_min_alarm_status(struct cc2_data *data, long *val)
if (ret < 0)
return ret;
- if (data->rh_alarm.low_alarm) {
- *val = (measurement < min_hyst) ? 1 : 0;
- data->rh_alarm.low_alarm = *val;
- } else {
- *val = 0;
+ scoped_guard(mutex, &data->irq_lock) {
+ if (data->rh_alarm.low_alarm) {
+ *val = (measurement < min_hyst) ? 1 : 0;
+ data->rh_alarm.low_alarm = *val;
+ } else {
+ *val = 0;
+ }
}
return 0;
@@ -554,11 +566,13 @@ static int cc2_humidity_max_alarm_status(struct cc2_data *data, long *val)
if (ret < 0)
return ret;
- if (data->rh_alarm.high_alarm) {
- *val = (measurement > max_hyst) ? 1 : 0;
- data->rh_alarm.high_alarm = *val;
- } else {
- *val = 0;
+ scoped_guard(mutex, &data->irq_lock) {
+ if (data->rh_alarm.high_alarm) {
+ *val = (measurement > max_hyst) ? 1 : 0;
+ data->rh_alarm.high_alarm = *val;
+ } else {
+ *val = 0;
+ }
}
return 0;
@@ -721,6 +735,8 @@ static int cc2_probe(struct i2c_client *client)
i2c_set_clientdata(client, data);
+ mutex_init(&data->irq_lock);
+
data->client = client;
data->regulator = devm_regulator_get_exclusive(dev, "vdd");
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 6.18.y 3/3] hwmon: chipcap2: synchronize ready IRQ state
2026-11-12 5:13 ` [PATCH 6.18.y 1/3] hwmon: (chipcap2) Drop unnecessary include files Sasha Levin
2026-11-12 5:13 ` [PATCH 6.18.y 2/3] hwmon: chipcap2: serialize access to the alarm indicators Sasha Levin
@ 2026-11-12 5:13 ` Sasha Levin
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2026-11-12 5:13 UTC (permalink / raw)
To: stable; +Cc: Javier Carrasco, Guenter Roeck, Sasha Levin
From: Javier Carrasco <javier.carrasco.cruz@gmail.com>
[ Upstream commit 8c02722be2caa6604a837b81faeaba78250eda4a ]
The ready IRQ handler can race with reinit_completion() in the enable
path. In particular, a handler from an earlier operation can complete
the completion after it is reset for a new operation.
Use irq_lock to serialize access to the completion and process_irqs.
Disable IRQ processing and synchronize any running handler before resetting
the completion for a new operation.
Fixes: 3af350929e75 ("hwmon: Add support for Amphenol ChipCap 2")
Cc: stable@vger.kernel.org
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20261014-chipcap2_locks-v3-11-27ebfc2c5b9e@gmail.com
[groeck: Dropped obsolete 'Assisted-by: tag]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/chipcap2.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/drivers/hwmon/chipcap2.c b/drivers/hwmon/chipcap2.c
index 49df66728ae9d..3eee0e41e1e4f 100644
--- a/drivers/hwmon/chipcap2.c
+++ b/drivers/hwmon/chipcap2.c
@@ -120,6 +120,16 @@ static int cc2_enable(struct cc2_data *data)
{
int ret;
+ if (data->irq_ready > 0) {
+ scoped_guard(mutex, &data->irq_lock)
+ data->process_irqs = false;
+
+ synchronize_irq(data->irq_ready);
+
+ scoped_guard(mutex, &data->irq_lock)
+ reinit_completion(&data->complete);
+ }
+
/* exclusive regulator, check in case a disable failed */
if (data->regulator_enabled) {
scoped_guard(mutex, &data->irq_lock)
@@ -127,9 +137,6 @@ static int cc2_enable(struct cc2_data *data)
return 0;
}
- /* clear any pending completion */
- try_wait_for_completion(&data->complete);
-
ret = regulator_enable(data->regulator);
if (ret < 0)
return ret;
@@ -159,6 +166,9 @@ static void cc2_disable(struct cc2_data *data)
scoped_guard(mutex, &data->irq_lock)
data->process_irqs = false;
+ if (data->irq_ready > 0)
+ synchronize_irq(data->irq_ready);
+
/* exclusive regulator, check in case an enable failed */
if (!data->regulator_enabled)
return;
@@ -498,8 +508,10 @@ static irqreturn_t cc2_ready_interrupt(int irq, void *data)
{
struct cc2_data *cc2 = data;
- if (cc2->process_irqs)
- complete(&cc2->complete);
+ scoped_guard(mutex, &cc2->irq_lock) {
+ if (cc2->process_irqs)
+ complete(&cc2->complete);
+ }
return IRQ_HANDLED;
}
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread