Re: [PATCH] gpiolib: clear the event clock flags when a line is released

[Adrian Ambrozewicz]

On Mon, Oct 12, 2026 at 02:05:49PM +0000, sashiko-bot@xxxxxxxxxx wrote:
> In gpiod_free_commit(), the ownership synchronization token
> (GPIOD_FLAG_REQUESTED) is cleared in desc->flags via a WRITE_ONCE() before
> the function finishes cleaning up ancillary state (debounce_period_us) and
> emitting the GPIO_V2_LINE_CHANGED_RELEASED notification:

This is real, and older than this patch: once the cleared
GPIOD_FLAG_REQUESTED is visible, a new request can set
desc->debounce_period_us in edge_detector_setup() before the old one
resets it to 0, and the debounce code reads the period from there.

I'll send a fix with v2 of the chip-removal series, which touches the
same function: reset the period first, then write the flags with
release ordering, pairing with the test_and_set_bit() in
gpiod_request_commit(), so that a new owner sees the reset. The
RELEASED notification can still arrive after the new request's
REQUESTED one. Moving it before the flags update would report the line
as still requested in the RELEASED event, so the fix will describe
that rather than reorder it.

Adrian