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From: Shuah Khan <skhan@linuxfoundation.org>
To: shuah@kernel.org, keescook@chromium.org, gregkh@linuxfoundation.org
Cc: Shuah Khan <skhan@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: [PATCH 02/11] selftests:lib:test_counters: add new test for counters
Date: Fri, 25 Sep 2020 17:47:16 -0600	[thread overview]
Message-ID: <219e13d8e2d28da79f1e3d5d6dcf0b5012e56427.1601073127.git.skhan@linuxfoundation.org> (raw)
In-Reply-To: <cover.1601073127.git.skhan@linuxfoundation.org>

Add a new selftest for testing counter_simple* and counter_atomic*
Counters API. This test load test_counters test modules and unloads.

The test module runs tests and prints results in dmesg.

There are a number of atomic_t usages in the kernel where atomic_t api
is used strictly for counting and not for managing object lifetime. In
some cases, atomic_t might not even be needed.

The purpose of these counters is twofold: 1. clearly differentiate
atomic_t counters from atomic_t usages that guard object lifetimes,
hence prone to overflow and underflow errors. It allows tools that scan
for underflow and overflow on atomic_t usages to detect overflow and
underflows to scan just the cases that are prone to errors. 2. provides
non-atomic counters for cases where atomic isn't necessary.

Simple atomic and non-atomic counters api provides interfaces for simple
atomic and non-atomic counters that just count, and don't guard resource
lifetimes. Counters 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.

Using counter_atomic* to guard lifetimes could lead to use-after free
when it overflows and undefined behavior when used to manage state
changes and device usage/open states.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
---
 MAINTAINERS                                  | 1 +
 tools/testing/selftests/lib/Makefile         | 1 +
 tools/testing/selftests/lib/config           | 1 +
 tools/testing/selftests/lib/test_counters.sh | 5 +++++
 4 files changed, 8 insertions(+)
 create mode 100755 tools/testing/selftests/lib/test_counters.sh

diff --git a/MAINTAINERS b/MAINTAINERS
index 886ee9b5f164..b308e80a1391 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15847,6 +15847,7 @@ L:	linux-kernel@vger.kernel.org
 S:	Maintained
 F:	include/linux/counters.h
 F:	lib/test_counters.c
+F:	tools/testing/selftests/lib/test_counters.sh
 
 SIMPLE FIRMWARE INTERFACE (SFI)
 S:	Obsolete
diff --git a/tools/testing/selftests/lib/Makefile b/tools/testing/selftests/lib/Makefile
index a105f094676e..e8960d7934e2 100644
--- a/tools/testing/selftests/lib/Makefile
+++ b/tools/testing/selftests/lib/Makefile
@@ -5,5 +5,6 @@
 all:
 
 TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh strscpy.sh
+TEST_PROGS += test_counters.sh
 
 include ../lib.mk
diff --git a/tools/testing/selftests/lib/config b/tools/testing/selftests/lib/config
index b80ee3f6e265..6ed25024d371 100644
--- a/tools/testing/selftests/lib/config
+++ b/tools/testing/selftests/lib/config
@@ -3,3 +3,4 @@ CONFIG_TEST_BITMAP=m
 CONFIG_PRIME_NUMBERS=m
 CONFIG_TEST_STRSCPY=m
 CONFIG_TEST_BITOPS=m
+CONFIG_TEST_COUNTERS=m
diff --git a/tools/testing/selftests/lib/test_counters.sh b/tools/testing/selftests/lib/test_counters.sh
new file mode 100755
index 000000000000..d1a130190e3f
--- /dev/null
+++ b/tools/testing/selftests/lib/test_counters.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Tests the Simple Atomic and Non-atomic Counters interfaces using
+# test_counters kernel module
+$(dirname $0)/../kselftest/module.sh "test_counters" test_counters
-- 
2.25.1


  parent reply	other threads:[~2020-09-25 23:47 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25 23:47 [PATCH 00/11] Introduce Simple atomic and non-atomic counters Shuah Khan
2020-09-25 23:47 ` Shuah Khan
2020-09-25 23:47 ` [PATCH 01/11] counters: Introduce counter_simple* and counter_atomic* counters Shuah Khan
2020-09-25 23:47 ` Shuah Khan [this message]
2020-09-25 23:47 ` [PATCH 03/11] drivers/base: convert deferred_trigger_count and probe_count to counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 04/11] drivers/base/devcoredump: convert devcd_count " Shuah Khan
2020-09-25 23:47 ` [PATCH 05/11] drivers/acpi: convert seqno counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 06/11] drivers/acpi/apei: " Shuah Khan
2020-09-25 23:47 ` [PATCH 07/11] drivers/android/binder: convert stats, transaction_log to counter_atomic32 Shuah Khan
2020-09-25 23:47   ` Shuah Khan
2020-09-27 23:39   ` Joel Fernandes
2020-09-27 23:39     ` Joel Fernandes
2020-09-25 23:47 ` [PATCH 08/11] drivers/base/test/test_async_driver_probe: convert to use counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 09/11] drivers/char/ipmi: convert stats " Shuah Khan
2020-09-26  0:15   ` Corey Minyard
2020-09-26  2:05     ` Shuah Khan
2020-09-25 23:47 ` [PATCH 10/11] drivers/misc/vmw_vmci: convert num guest devices counter to counter_atomic32 Shuah Khan
2020-09-25 23:47 ` [PATCH 11/11] drivers/edac: convert pci counters " Shuah Khan
2020-09-28 12:05   ` Borislav Petkov
2020-09-25 23:52 ` [PATCH 00/11] Introduce Simple atomic and non-atomic counters Kees Cook
2020-09-25 23:52   ` Kees Cook
2020-09-26  0:13   ` Shuah Khan
2020-09-26  0:13     ` Shuah Khan
2020-09-26 16:33     ` Kees Cook
2020-09-26 16:33       ` Kees Cook
2020-09-28 22:52       ` Shuah Khan
2020-09-28 22:52         ` Shuah Khan
2020-09-26 16:22 ` Kees Cook
2020-09-26 16:22   ` Kees Cook
2020-09-28 22:42   ` Shuah Khan
2020-09-28 22:42     ` Shuah Khan
2020-09-26 16:29 ` Kees Cook
2020-09-26 16:29   ` Kees Cook
2020-09-28 22:41   ` Shuah Khan
2020-09-28 22:41     ` Shuah Khan
2020-09-28 23:13     ` Kees Cook
2020-09-28 23:13       ` Kees Cook
2020-10-06 15:21       ` Shuah Khan
2020-10-06 15:21         ` Shuah Khan
2020-09-27 23:35 ` Joel Fernandes
2020-09-27 23:35   ` Joel Fernandes
2020-09-28 20:34   ` Kees Cook
2020-09-28 20:34     ` Kees Cook
2020-09-28 21:17     ` Joel Fernandes
2020-09-28 21:17       ` Joel Fernandes
2020-09-28 23:01       ` Shuah Khan
2020-09-28 23:01         ` Shuah Khan

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