linux-kernel - Re: [PATCH v2 07/18] gpiolib: cdev: support edge detection for uAPI v2

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 4 Aug 2020 21:28:04 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Kent Gibson <warthog618@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v2 07/18] gpiolib: cdev: support edge detection for uAPI v2

On Sat, Jul 25, 2020 at 6:21 AM Kent Gibson <warthog618@...il.com> wrote:
>
> Add support for edge detection to lines requested using
> GPIO_GET_LINE_IOCTL.
>
> Signed-off-by: Kent Gibson <warthog618@...il.com>
> ---

[snip!]

> +
> +static irqreturn_t edge_irq_thread(int irq, void *p)
> +{
> +       struct edge_detector *edet = p;
> +       struct line *line = edet->line;
> +       struct gpio_desc *desc = edge_detector_desc(edet);
> +       struct gpioline_event le;
> +       int ret;
> +
> +       /* Do not leak kernel stack to userspace */
> +       memset(&le, 0, sizeof(le));
> +
> +       /*
> +        * We may be running from a nested threaded interrupt in which case
> +        * we didn't get the timestamp from edge_irq_handler().
> +        */
> +       if (!edet->timestamp) {
> +               le.timestamp = ktime_get_ns();

IIRC Marc suggested using smp_rmw() here before reading the timestamp.
Do we still need it or something changed?

Bartosz