From: William Breathitt Gray <wbg@kernel.org>
To: William Breathitt Gray <william.gray@linaro.org>
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
jic23@kernel.org, lars@metafoo.de, stable@vger.kernel.org
Subject: Re: [PATCH 6.1,6.2,6.3 v3 1/6] counter: 104-quad-8: Fix race condition between FLAG and CNTR reads
Date: Sat, 18 Mar 2023 09:27:56 -0400 [thread overview]
Message-ID: <ZBW8XN71fYwJe6rW@ishi> (raw)
In-Reply-To: <20230312231554.134858-1-william.gray@linaro.org>
[-- Attachment #1: Type: text/plain, Size: 989 bytes --]
On Sun, Mar 12, 2023 at 07:15:49PM -0400, William Breathitt Gray wrote:
> The Counter (CNTR) register is 24 bits wide, but we can have an
> effective 25-bit count value by setting bit 24 to the XOR of the Borrow
> flag and Carry flag. The flags can be read from the FLAG register, but a
> race condition exists: the Borrow flag and Carry flag are instantaneous
> and could change by the time the count value is read from the CNTR
> register.
>
> Since the race condition could result in an incorrect 25-bit count
> value, remove support for 25-bit count values from this driver;
> hard-coded maximum count values are replaced by a LS7267_CNTR_MAX define
> for consistency and clarity.
>
> Fixes: 28e5d3bb0325 ("iio: 104-quad-8: Add IIO support for the ACCES 104-QUAD-8")
> Cc: <stable@vger.kernel.org> # 6.1.x
> Cc: <stable@vger.kernel.org> # 6.2.x
> Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Applied to counter-fixes.
William Breathitt Gray
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]
prev parent reply other threads:[~2023-03-18 13:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-12 23:15 [PATCH 6.1,6.2,6.3 v3 1/6] counter: 104-quad-8: Fix race condition between FLAG and CNTR reads William Breathitt Gray
2023-03-12 23:15 ` [PATCH 5.15 v3 2/6] " William Breathitt Gray
2023-03-12 23:15 ` [PATCH 5.10 v3 3/6] " William Breathitt Gray
2023-03-12 23:15 ` [PATCH 5.4 v3 4/6] " William Breathitt Gray
2023-03-12 23:15 ` [PATCH 4.19 v3 5/6] iio: " William Breathitt Gray
2023-03-12 23:15 ` [PATCH 4.14 v3 6/6] " William Breathitt Gray
2023-03-18 13:27 ` William Breathitt Gray [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZBW8XN71fYwJe6rW@ishi \
--to=wbg@kernel.org \
--cc=jic23@kernel.org \
--cc=lars@metafoo.de \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=william.gray@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox