From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC5852FE042; Tue, 31 Mar 2026 17:05:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774976721; cv=none; b=Gap6szJFlB9w/MMarAdj+XCtOeWlDgY3vf1wGwksFa6IJWKWgrtG+tuZFNM0RAb4s6RJDtAXBpBZyZ+hmlJEudnpZI+ZS72KSypXARQWPI5ZiLiy3CsqMdRC4vlTig8cc5k5gdSBsvlyOCCMzvm6gAI8Pu6EybDe7dGW0L51mPs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774976721; c=relaxed/simple; bh=CmN6hc+ZGiiwS1uUmhK23aoLSFiO1T88hALr7562Dp8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kaNeGoOeZPdpi4A9BRlL3If+kvd8Gzrl5D7Rz10IHzsGMalJZ9oJQxBjhGV7vNtiwsrENQeA95Z8G77Sxzy20zjFfHu0ekEqHeJ4MRKgPD9H0Tx2Rl9i3Yyg3tnxCygPhsp3GVZzi8crCJPVrfr/1f/DVvz1Yk06Vsqu+/xM7hE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1w6VUKfg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1w6VUKfg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 726D2C19423; Tue, 31 Mar 2026 17:05:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774976721; bh=CmN6hc+ZGiiwS1uUmhK23aoLSFiO1T88hALr7562Dp8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1w6VUKfgtB+pSIPOsZCMjLTlExy6U2Ko5jilOblQqmhiL1tEHK//QYNhWDb6EsMc2 9+S1Ys9cUMDBeThIGjVx5DlbHqaKpSPb+mqQcW5mVJfkyzQ5nohErLo3L+d1wVPTCQ dlvCcsl23TjGLxT5PYpGdU3rBRctNOstZJfqRV4g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sanman Pradhan , Guenter Roeck , Sasha Levin Subject: [PATCH 6.18 169/309] hwmon: (pmbus/core) Protect regulator operations with mutex Date: Tue, 31 Mar 2026 18:21:12 +0200 Message-ID: <20260331161759.687315510@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161753.468533260@linuxfoundation.org> References: <20260331161753.468533260@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guenter Roeck [ Upstream commit 754bd2b4a084b90b5e7b630e1f423061a9b9b761 ] The regulator operations pmbus_regulator_get_voltage(), pmbus_regulator_set_voltage(), and pmbus_regulator_list_voltage() access PMBus registers and shared data but were not protected by the update_lock mutex. This could lead to race conditions. However, adding mutex protection directly to these functions causes a deadlock because pmbus_regulator_notify() (which calls regulator_notifier_call_chain()) is often called with the mutex already held (e.g., from pmbus_fault_handler()). If a regulator callback then calls one of the now-protected voltage functions, it will attempt to acquire the same mutex. Rework pmbus_regulator_notify() to utilize a worker function to send notifications outside of the mutex protection. Events are stored as atomics in a per-page bitmask and processed by the worker. Initialize the worker and its associated data during regulator registration, and ensure it is cancelled on device removal using devm_add_action_or_reset(). While at it, remove the unnecessary include of linux/of.h. Cc: Sanman Pradhan Fixes: ddbb4db4ced1b ("hwmon: (pmbus) Add regulator support") Reviewed-by: Sanman Pradhan Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin --- drivers/hwmon/pmbus/pmbus_core.c | 114 ++++++++++++++++++++++++------- 1 file changed, 89 insertions(+), 25 deletions(-) diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index cbc36f0ba4bf9..572be3ebc03df 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -6,6 +6,7 @@ * Copyright (c) 2012 Guenter Roeck */ +#include #include #include #include @@ -21,8 +22,8 @@ #include #include #include -#include #include +#include #include "pmbus.h" /* @@ -112,6 +113,11 @@ struct pmbus_data { struct mutex update_lock; +#if IS_ENABLED(CONFIG_REGULATOR) + atomic_t regulator_events[PMBUS_PAGES]; + struct work_struct regulator_notify_work; +#endif + bool has_status_word; /* device uses STATUS_WORD register */ int (*read_status)(struct i2c_client *client, int page); @@ -3228,12 +3234,19 @@ static int pmbus_regulator_get_voltage(struct regulator_dev *rdev) .class = PSC_VOLTAGE_OUT, .convert = true, }; + int ret; + mutex_lock(&data->update_lock); s.data = _pmbus_read_word_data(client, s.page, 0xff, PMBUS_READ_VOUT); - if (s.data < 0) - return s.data; + if (s.data < 0) { + ret = s.data; + goto unlock; + } - return (int)pmbus_reg2data(data, &s) * 1000; /* unit is uV */ + ret = (int)pmbus_reg2data(data, &s) * 1000; /* unit is uV */ +unlock: + mutex_unlock(&data->update_lock); + return ret; } static int pmbus_regulator_set_voltage(struct regulator_dev *rdev, int min_uv, @@ -3250,16 +3263,22 @@ static int pmbus_regulator_set_voltage(struct regulator_dev *rdev, int min_uv, }; int val = DIV_ROUND_CLOSEST(min_uv, 1000); /* convert to mV */ int low, high; + int ret; *selector = 0; + mutex_lock(&data->update_lock); low = pmbus_regulator_get_low_margin(client, s.page); - if (low < 0) - return low; + if (low < 0) { + ret = low; + goto unlock; + } high = pmbus_regulator_get_high_margin(client, s.page); - if (high < 0) - return high; + if (high < 0) { + ret = high; + goto unlock; + } /* Make sure we are within margins */ if (low > val) @@ -3269,7 +3288,10 @@ static int pmbus_regulator_set_voltage(struct regulator_dev *rdev, int min_uv, val = pmbus_data2reg(data, &s, val); - return _pmbus_write_word_data(client, s.page, PMBUS_VOUT_COMMAND, (u16)val); + ret = _pmbus_write_word_data(client, s.page, PMBUS_VOUT_COMMAND, (u16)val); +unlock: + mutex_unlock(&data->update_lock); + return ret; } static int pmbus_regulator_list_voltage(struct regulator_dev *rdev, @@ -3279,6 +3301,7 @@ static int pmbus_regulator_list_voltage(struct regulator_dev *rdev, struct i2c_client *client = to_i2c_client(dev->parent); struct pmbus_data *data = i2c_get_clientdata(client); int val, low, high; + int ret; if (data->flags & PMBUS_VOUT_PROTECTED) return 0; @@ -3291,18 +3314,29 @@ static int pmbus_regulator_list_voltage(struct regulator_dev *rdev, val = DIV_ROUND_CLOSEST(rdev->desc->min_uV + (rdev->desc->uV_step * selector), 1000); /* convert to mV */ + mutex_lock(&data->update_lock); + low = pmbus_regulator_get_low_margin(client, rdev_get_id(rdev)); - if (low < 0) - return low; + if (low < 0) { + ret = low; + goto unlock; + } high = pmbus_regulator_get_high_margin(client, rdev_get_id(rdev)); - if (high < 0) - return high; + if (high < 0) { + ret = high; + goto unlock; + } - if (val >= low && val <= high) - return val * 1000; /* unit is uV */ + if (val >= low && val <= high) { + ret = val * 1000; /* unit is uV */ + goto unlock; + } - return 0; + ret = 0; +unlock: + mutex_unlock(&data->update_lock); + return ret; } const struct regulator_ops pmbus_regulator_ops = { @@ -3333,12 +3367,42 @@ int pmbus_regulator_init_cb(struct regulator_dev *rdev, } EXPORT_SYMBOL_NS_GPL(pmbus_regulator_init_cb, "PMBUS"); +static void pmbus_regulator_notify_work_cancel(void *data) +{ + struct pmbus_data *pdata = data; + + cancel_work_sync(&pdata->regulator_notify_work); +} + +static void pmbus_regulator_notify_worker(struct work_struct *work) +{ + struct pmbus_data *data = + container_of(work, struct pmbus_data, regulator_notify_work); + int i, j; + + for (i = 0; i < data->info->pages; i++) { + int event; + + event = atomic_xchg(&data->regulator_events[i], 0); + if (!event) + continue; + + for (j = 0; j < data->info->num_regulators; j++) { + if (i == rdev_get_id(data->rdevs[j])) { + regulator_notifier_call_chain(data->rdevs[j], + event, NULL); + break; + } + } + } +} + static int pmbus_regulator_register(struct pmbus_data *data) { struct device *dev = data->dev; const struct pmbus_driver_info *info = data->info; const struct pmbus_platform_data *pdata = dev_get_platdata(dev); - int i; + int i, ret; data->rdevs = devm_kzalloc(dev, sizeof(struct regulator_dev *) * info->num_regulators, GFP_KERNEL); @@ -3362,19 +3426,19 @@ static int pmbus_regulator_register(struct pmbus_data *data) info->reg_desc[i].name); } + INIT_WORK(&data->regulator_notify_work, pmbus_regulator_notify_worker); + + ret = devm_add_action_or_reset(dev, pmbus_regulator_notify_work_cancel, data); + if (ret) + return ret; + return 0; } static void pmbus_regulator_notify(struct pmbus_data *data, int page, int event) { - int j; - - for (j = 0; j < data->info->num_regulators; j++) { - if (page == rdev_get_id(data->rdevs[j])) { - regulator_notifier_call_chain(data->rdevs[j], event, NULL); - break; - } - } + atomic_or(event, &data->regulator_events[page]); + schedule_work(&data->regulator_notify_work); } #else static int pmbus_regulator_register(struct pmbus_data *data) -- 2.53.0