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Date:   Wed, 30 Mar 2022 18:49:33 -0300
From:   Marcelo Schmitt <marcelo.schmitt1@gmail.com>
To:     corbet@lwn.net, mchehab+huawei@kernel.org, dlatypov@google.com,
        davidgow@google.com
Cc:     linux-doc@vger.kernel.org, linux-sparse@vger.kernel.org,
        cocci@inria.fr, smatch@vger.kernel.org,
        linux-kernel@vger.kernel.org, skhan@linuxfoundation.org,
        dan.carpenter@oracle.com, julia.lawall@inria.fr
Subject: [PATCH v3 1/2] Documentation: dev-tools: Add a section for static
 analysis tools
Message-ID: <7d793c1b9f87d9cb8ac0e858e561e108c2bf0176.1648674305.git.marcelo.schmitt1@gmail.com>
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Complement the Kernel Testing Guide documentation page by adding a
section about static analysis tools.

Signed-off-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Acked-by: Daniel Latypov <dlatypov@google.com>
Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Julia Lawall <julia.lawall@inria.fr>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
---
Change log v2 -> v3:
- Added Julia's acknowledgment tag

Change log v1 -> v2:
- Brought generic tool characteristics to the intro paragraph
- Made explicit that these tools run at compile time
- Added a note of caution about false positives
- Updated Coccinelle info to make it sound better and be more skimmable

 Documentation/dev-tools/testing-overview.rst | 31 ++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/Documentation/dev-tools/testing-overview.rst b/Documentation/dev-tools/testing-overview.rst
index 65feb81edb14..b5e02dd3fd94 100644
--- a/Documentation/dev-tools/testing-overview.rst
+++ b/Documentation/dev-tools/testing-overview.rst
@@ -115,3 +115,34 @@ that none of these errors are occurring during the test.
 Some of these tools integrate with KUnit or kselftest and will
 automatically fail tests if an issue is detected.
 
+Static Analysis Tools
+=====================
+
+In addition to testing a running kernel, one can also analyze kernel source code
+directly (**at compile time**) using **static analysis** tools. The tools
+commonly used in the kernel allow one to inspect the whole source tree or just
+specific files within it. They make it easier to detect and fix problems during
+the development process.
+
+Sparse can help test the kernel by performing type-checking, lock checking,
+value range checking, in addition to reporting various errors and warnings while
+examining the code. See the Documentation/dev-tools/sparse.rst documentation
+page for details on how to use it.
+
+Smatch extends Sparse and provides additional checks for programming logic
+mistakes such as missing breaks in switch statements, unused return values on
+error checking, forgetting to set an error code in the return of an error path,
+etc. Smatch also has tests against more serious issues such as integer
+overflows, null pointer dereferences, and memory leaks. See the project page at
+http://smatch.sourceforge.net/.
+
+Coccinelle is another static analyzer at our disposal. Coccinelle is often used
+to aid refactoring and collateral evolution of source code, but it can also help
+to avoid certain bugs that occur in common code patterns. The types of tests
+available include API tests, tests for correct usage of kernel iterators, checks
+for the soundness of free operations, analysis of locking behavior, and further
+tests known to help keep consistent kernel usage. See the
+Documentation/dev-tools/coccinelle.rst documentation page for details.
+
+Beware, though, that static analysis tools suffer from **false positives**.
+Errors and warns need to be evaluated carefully before attempting to fix them.
-- 
2.35.1