Re: [PATCH 6.6.y] hwmon: (pmbus/core) Protect regulator operations with mutex

[sashiko-bot@kernel.org]

> From: Guenter Roeck <linux@roeck-us.net>
> 
> [ 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.
> [ ... ]
> Cc: Sanman Pradhan <psanman@juniper.net>
> Fixes: ddbb4db4ced1b ("hwmon: (pmbus) Add regulator support")
> Reviewed-by: Sanman Pradhan <psanman@juniper.net>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> Signed-off-by: Fang Wang <32840572@qq.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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