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Date:   Fri, 21 Apr 2023 12:02:16 +0800
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Message-ID: <20230421040218.2156548-2-davidgow@google.com>
Subject: [PATCH v3 2/4] Documentation: kunit: Note that assertions should not
 be used in cleanup
From:   David Gow <davidgow@google.com>
To:     Benjamin Berg <benjamin@sipsolutions.net>,
        Brendan Higgins <brendan.higgins@linux.dev>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Rae Moar <rmoar@google.com>,
        Daniel Latypov <dlatypov@google.com>
Cc:     David Gow <davidgow@google.com>, maxime@cerno.tech,
        Stephen Boyd <sboyd@kernel.org>, kunit-dev@googlegroups.com,
        linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
        Sadiya Kazi <sadiyakazi@google.com>
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Precedence: bulk

As assertions abort the test cleanup process, they should be avoided
from within a suite's exit function, or from within resource 'free'
functions. Unlike with initialisation or main test execution, no further
cleanup will be performed after a failed assertion, potentially causing
a leak of resources.

Signed-off-by: David Gow <davidgow@google.com>
---

No changes since v2:
https://lore.kernel.org/linux-kselftest/20230419085426.1671703-2-davidgow@google.com/

This patch was introduced in v2.

---
 Documentation/dev-tools/kunit/usage.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst
index 9faf2b4153fc..9f720f1317d3 100644
--- a/Documentation/dev-tools/kunit/usage.rst
+++ b/Documentation/dev-tools/kunit/usage.rst
@@ -121,6 +121,12 @@ there's an allocation error.
    ``return`` so they only work from the test function. In KUnit, we stop the
    current kthread on failure, so you can call them from anywhere.
 
+.. note::
+   Warning: There is an exception to the above rule. You shouldn't use assertions
+   in the suite's exit() function, or in the free function for a resource. These
+   run when a test is shutting down, and an assertion here prevents further
+   cleanup code from running, potentially leading to a memory leak.
+
 Customizing error messages
 --------------------------
 
-- 
2.40.0.634.g4ca3ef3211-goog