Re: [PATCH v3 1/4] kunit: Always run cleanup from a test kthread

From: Maxime Ripard <maxime@cerno.tech>
To: David Gow <davidgow@google.com>
Cc: 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>,
	Stephen Boyd <sboyd@kernel.org>,
	kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org, Sadiya Kazi <sadiyakazi@google.com>
Subject: Re: [PATCH v3 1/4] kunit: Always run cleanup from a test kthread
Date: Tue, 25 Apr 2023 17:47:11 +0200	[thread overview]
Message-ID: <ugim4ef5kbcamojrhq4ryun5wjktcd2rgnfxt7k64hg2y7bkle@ej4mcwflmqbv> (raw)
In-Reply-To: <20230421040218.2156548-1-davidgow@google.com>

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On Fri, Apr 21, 2023 at 12:02:15PM +0800, David Gow wrote:
> KUnit tests run in a kthread, with the current->kunit_test pointer set
> to the test's context. This allows the kunit_get_current_test() and
> kunit_fail_current_test() macros to work. Normally, this pointer is
> still valid during test shutdown (i.e., the suite->exit function, and
> any resource cleanup). However, if the test has exited early (e.g., due
> to a failed assertion), the cleanup is done in the parent KUnit thread,
> which does not have an active context.
> 
> Instead, in the event test terminates early, run the test exit and
> cleanup from a new 'cleanup' kthread, which sets current->kunit_test,
> and better isolates the rest of KUnit from issues which arise in test
> cleanup.
> 
> If a test cleanup function itself aborts (e.g., due to an assertion
> failing), there will be no further attempts to clean up: an error will
> be logged and the test failed. For example:
> 	 # example_simple_test: test aborted during cleanup. continuing without cleaning up
> 
> This should also make it easier to get access to the KUnit context,
> particularly from within resource cleanup functions, which may, for
> example, need access to data in test->priv.
> 
> Signed-off-by: David Gow <davidgow@google.com>

Thanks for doing this. I've tested it with an action that needs the test
priv pointer, and it works as expected

Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Maxime Ripard <maxime@cerno.tech>

Thanks!
Maxime

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