linux-kernel - Re: [PATCH] kunit: Protect string comparisons against NULL

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Message-ID: <c6a4c016-e889-422c-91aa-91568f6667f4@opensource.cirrus.com>
Date: Thu, 4 Jan 2024 11:52:28 +0000
From: Richard Fitzgerald <rf@...nsource.cirrus.com>
To: David Gow <davidgow@...gle.com>
CC: <brendan.higgins@...ux.dev>, <rmoar@...gle.com>,
        <linux-kselftest@...r.kernel.org>, <kunit-dev@...glegroups.com>,
        <linux-kernel@...r.kernel.org>, <patches@...nsource.cirrus.com>
Subject: Re: [PATCH] kunit: Protect string comparisons against NULL

On 22/12/23 08:39, David Gow wrote:
> On Wed, 20 Dec 2023 at 23:52, Richard Fitzgerald
> <rf@...nsource.cirrus.com> wrote:
>>
>> Add NULL checks to KUNIT_BINARY_STR_ASSERTION() so that it will fail
>> cleanly if either pointer is NULL, instead of causing a NULL pointer
>> dereference in the strcmp().
>>
>> A test failure could be that a string is unexpectedly NULL. This could
>> be trapped by KUNIT_ASSERT_NOT_NULL() but that would terminate the test
>> at that point. It's preferable that the KUNIT_EXPECT_STR*() macros can
>> handle NULL pointers as a failure.
>>
>> Signed-off-by: Richard Fitzgerald <rf@...nsource.cirrus.com>
>> ---
> 
> I think this is the right thing to do. There's possibly an argument
> that this should succeed if both are NULL, but I prefer it this way.
> 

Maybe an _OR_NULL() variant of the string test macros would be better to
be explicit that NULL is acceptable.

> Reviewed-by: David Gow <davidgow@...gle.com>
> 
> Cheers,
> -- David