From: Kees Cook <keescook@chromium.org>
To: Shuah Khan <skhan@linuxfoundation.org>
Cc: rafael@kernel.org, james.morse@arm.com, tony.luck@intel.com,
bp@alien8.de, gregkh@linuxfoundation.org,
linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH v2 06/11] drivers/acpi/apei: convert seqno counter_atomic32
Date: Wed, 7 Oct 2020 11:17:20 -0700 [thread overview]
Message-ID: <202010071117.B0C6EA7A0@keescook> (raw)
In-Reply-To: <884f1fddfbc1a991f5f5bbada3ea63c1e3afab20.1602011710.git.skhan@linuxfoundation.org>
On Tue, Oct 06, 2020 at 02:44:37PM -0600, Shuah Khan wrote:
> counter_atomic* is introduced to be used when a variable is used as
> a simple counter and doesn't guard object lifetimes. This clearly
> differentiates atomic_t usages that guard object lifetimes.
>
> counter_atomic* variables will wrap around to 0 when it overflows and
> should not be used to guard resource lifetimes, device usage and
> open counts that control state changes, and pm states.
>
> seqno is a sequence number counter for logging. This counter gets
> incremented. Unsure if there is a chance of this overflowing. It
> doesn't look like overflowing causes any problems since it is used
> to tag the log messages and nothing more.
>
> Convert it to use counter_atomic32.
>
> This conversion doesn't change the overflow wrap around behavior.
>
> Acked-by: Rafael J. Wysocki <rafael@kernel.org>
> Acked-by: Borislav Petkov <bp@suse.de>
> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Yup, also logging only, it seems.
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2020-10-07 18:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 20:44 [PATCH v2 00/11] Introduce Simple atomic counters Shuah Khan
2020-10-06 20:44 ` [PATCH v2 05/11] drivers/acpi: convert seqno counter_atomic32 Shuah Khan
2020-10-07 18:16 ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 06/11] drivers/acpi/apei: " Shuah Khan
2020-10-07 18:17 ` Kees Cook [this message]
2020-10-07 18:30 ` [PATCH v2 00/11] Introduce Simple atomic counters Kees Cook
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