From: Kees Cook <keescook@chromium.org>
To: Shuah Khan <skhan@linuxfoundation.org>
Cc: johannes@sipsolutions.net, gregkh@linuxfoundation.org,
rafael@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 04/11] drivers/base/devcoredump: convert devcd_count to counter_atomic32
Date: Wed, 7 Oct 2020 11:15:44 -0700 [thread overview]
Message-ID: <202010071114.EE9A2A47C@keescook> (raw)
In-Reply-To: <462fd514dfe2afbb8faa1dea4cdb4b0e75d8e8da.1602011710.git.skhan@linuxfoundation.org>
On Tue, Oct 06, 2020 at 02:44:35PM -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.
>
> devcd_count is used to track dev_coredumpm device count and used in
> device name string. It doesn't guard object lifetimes, device usage
> counts, device open counts, and pm states. There is very little chance
> of this counter overflowing. Convert it to use counter_atomic32.
>
> This conversion doesn't change the overflow wrap around behavior.
>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
I actually wonder if this should use refcount_t just because it is
designed to be an alway-unique value. It is hard to imagine ever causing
this to overflow, but why not let it be protected?
--
Kees Cook
next prev parent reply other threads:[~2020-10-07 18:15 UTC|newest]
Thread overview: 36+ 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 01/11] counters: Introduce counter_atomic* counters Shuah Khan
2020-10-07 9:04 ` Greg KH
2020-10-08 17:18 ` Shuah Khan
2020-10-07 18:11 ` Kees Cook
2020-10-07 19:26 ` Shuah Khan
2020-10-07 20:30 ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 02/11] selftests:lib:test_counters: add new test for counters Shuah Khan
2020-10-07 18:12 ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 03/11] drivers/base: convert deferred_trigger_count and probe_count to counter_atomic32 Shuah Khan
2020-10-07 18:13 ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 04/11] drivers/base/devcoredump: convert devcd_count " Shuah Khan
2020-10-07 18:15 ` Kees Cook [this message]
2020-10-07 19:33 ` Shuah Khan
2020-10-07 19:38 ` Johannes Berg
2020-10-07 19:59 ` Shuah Khan
2020-10-07 20:43 ` Kees Cook
2020-10-08 6:42 ` Johannes Berg
2020-10-08 7:37 ` Kees Cook
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
2020-10-06 20:44 ` [PATCH v2 07/11] drivers/android/binder: convert stats, transaction_log to counter_atomic32 Shuah Khan
2020-10-07 18:18 ` Kees Cook
2020-10-09 12:39 ` Christian Brauner
2020-10-06 20:44 ` [PATCH v2 08/11] drivers/base/test/test_async_driver_probe: convert to use counter_atomic32 Shuah Khan
2020-10-07 18:20 ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 09/11] drivers/char/ipmi: convert stats " Shuah Khan
2020-10-07 18:21 ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 10/11] drivers/misc/vmw_vmci: convert num guest devices counter to counter_atomic32 Shuah Khan
2020-10-07 18:27 ` Kees Cook
2020-10-08 17:12 ` Shuah Khan
2020-10-06 20:44 ` [PATCH v2 11/11] drivers/edac: convert pci counters " Shuah Khan
2020-10-07 18:28 ` Kees Cook
2020-10-07 18:30 ` [PATCH v2 00/11] Introduce Simple atomic counters Kees Cook
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