From: Linus Walleij <linus.walleij@linaro.org>
To: Dan Callaghan <dan.callaghan@opengear.com>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RESEND] gpiolib: hold gpio devices lock until ->descs array is initialised
Date: Thu, 23 Jan 2020 16:26:11 +0100 [thread overview]
Message-ID: <CACRpkdYGED-YU8PGUFwK-Arrs0Vp1=Oc-Nx=MvjuygLJvzQPkg@mail.gmail.com> (raw)
In-Reply-To: <20200121001216.15964-1-dan.callaghan@opengear.com>
On Tue, Jan 21, 2020 at 1:13 AM Dan Callaghan
<dan.callaghan@opengear.com> wrote:
> If a driver consuming the GPIO chip is being probed at the same time as
> the GPIO driver is registering the chip, it is possible for the
> consuming driver to see the ->descs array in an uninitialised state.
> For example, the gpio-keys-polled driver can fail like this:
>
> kernel: gpiod_request: invalid GPIO (no device)
> kernel: gpio-keys-polled PRP0001:07: failed to get gpio: -22
> kernel: gpio-keys-polled: probe of PRP0001:07 failed with error -22
>
> This patch makes gpiochip_add() hold the lock protecting gpio_devices
> until it has finished setting desc->gdev on the newly inserted list
> entry.
>
> Signed-off-by: Dan Callaghan <dan.callaghan@opengear.com>
> ---
> Resending this one because I failed to cc the maintainers on the
> original posting, sorry about that.
This makes a lot of sense, I'm impressed that you managed to
provoke this error!
Patch applied.
Yours,
Linus Walleij
prev parent reply other threads:[~2020-01-23 15:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 0:12 [PATCH RESEND] gpiolib: hold gpio devices lock until ->descs array is initialised Dan Callaghan
2020-01-23 15:26 ` Linus Walleij [this message]
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