Re: [PATCH] rtc: mpc5121: request IRQs after allocating the RTC device

[sashiko-bot@kernel.org]

> Probe requests both IRQs with devm_request_irq() before
> devm_rtc_allocate_device(). Devres releases resources in reverse order,
> so on unbind or probe failure the RTC device is put before the IRQs
> are freed. A handler running in that window passes the stale rtc->rtc
> to rtc_update_irq(), which schedules work on the freed device.
> 
> On unbind, remove() first disables the alarm and update interrupts, so
> only a handler already running on another CPU is affected. On a probe
> failure after the IRQs are requested, remove() does not run, and an
> alarm left pending, for example a wake alarm from before a reboot, can
> fire in that window.
> 
> Request the IRQs after the RTC device is allocated and set up, right
> before registering it, so devres frees them and waits for running
> handlers before releasing the device. An interrupt arriving before
> registration is harmless, as rtc_update_irq() only schedules work on
> an allocated device.
> 
> Fixes: d53d4ae981d0 ("rtc: mpc5121: simplify probe")
> Assisted-by: LLM
> Signed-off-by: Rosen Penev <rosenp@gmail.com>

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

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Sashiko AI review · https://sashiko.dev/#/patchset/20261004222907.437878-1-rosenp@gmail.com?part=1