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Wed, 14 Oct 2026 10:34:28 -0700 (PDT) Received: from [127.0.1.1] ([2001:4bb8:148:f08c:65a8:f8e5:f310:5a71]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c3ed963cecesm9381366b.21.2026.10.14.10.34.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Oct 2026 10:34:28 -0700 (PDT) From: Javier Carrasco Date: Wed, 14 Oct 2026 19:34:09 +0200 Subject: [PATCH v3 10/11] hwmon: chipcap2: serialize access to the alarm indicators Precedence: bulk X-Mailing-List: linux-hwmon@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261014-chipcap2_locks-v3-10-27ebfc2c5b9e@gmail.com> References: <20261014-chipcap2_locks-v3-0-27ebfc2c5b9e@gmail.com> In-Reply-To: <20261014-chipcap2_locks-v3-0-27ebfc2c5b9e@gmail.com> To: Guenter Roeck Cc: linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, Javier Carrasco , stable@vger.kernel.org X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1791999252; l=4456; i=javier.carrasco.cruz@gmail.com; s=20260924; h=from:subject:message-id; bh=PcOCiIxgYYpvwoyMWaozX6BsQL3pWei0zaNRsgiiGPA=; b=qvqS/uq+hwir8HDZjZVknIOfHkTB+05+LTVsSLASdvkqYGlJ/2vKgWvDwVLv5zK0sMgXJUR8d x2sqvg38owcCVK7aOkhuVDM1+qTiulD6aIOMmnEokNMVIyfWRg7UYQz X-Developer-Key: i=javier.carrasco.cruz@gmail.com; a=ed25519; pk=VV+hcMoOj1Sx6xSiY0W/FZNAskGZe2AagSMVj0PsmAs= 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 Assisted-by: opencode:claude-opus-5 --- 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 eba6469940ab..b3b725cc7224 100644 --- a/drivers/hwmon/chipcap2.c +++ b/drivers/hwmon/chipcap2.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -91,6 +92,8 @@ 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; }; @@ -122,7 +125,8 @@ 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; } @@ -137,7 +141,8 @@ 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; } @@ -154,7 +159,8 @@ 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) @@ -514,10 +520,12 @@ 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; @@ -527,10 +535,12 @@ 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; @@ -546,11 +556,13 @@ 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; @@ -566,11 +578,13 @@ 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; @@ -753,6 +767,8 @@ 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"); -- 2.43.0