Re: [PATCH 1/2] hwmon: (gigabyte_waterforce) Make status_report_request_lock IRQ safe

[sashiko-bot@kernel.org]

> waterforce_raw_event() is the HID ->raw_event() callback and acquires
> priv->status_report_request_lock with a plain spin_lock(), while
> waterforce_get_status() acquires the same lock with spin_lock_bh().
> 
> Depending on the HID transport and USB host controller driver,
> waterforce_raw_event() can run in process context (e.g. via uhid with
> softirqs and hardirqs enabled), softirq context (USB HCDs using HCD_BH),
> or hard interrupt context (USB HCDs without HCD_BH, such as OHCI/UHCI).
> 
> Because spin_lock_bh() in waterforce_get_status() leaves hard interrupts
> enabled, a hard-IRQ URB completion invoking waterforce_raw_event() on the
> same CPU will self-deadlock on status_report_request_lock. Likewise, a
> plain spin_lock() in waterforce_raw_event() when called from process
> context via uhid leaves both softirqs and hardirqs enabled, risking a
> self-deadlock if interrupted by softirq or hardirq raw-event delivery on
> the same CPU.
> 
> Use spin_lock_irq() in waterforce_get_status(), which always runs in
> process context, and spin_lock_irqsave() in waterforce_raw_event(), which
> may run with interrupts either enabled or disabled.
> 
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Fixes: 41c71105a845 ("hwmon: (gigabyte_waterforce) Mark status report as received under a spinlock")
> Cc: Aleksa Savic <savicaleksa83@gmail.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261031223131.1855967-1-linux@roeck-us.net?part=1