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From:   David Gow <davidgow@google.com>
Date:   Tue, 12 Jul 2022 21:29:55 +0800
Message-ID: <CABVgOSmvU1tOHBQDOr9vT-SSaM1k--mjck1-T-M_vWnDtWecDA@mail.gmail.com>
Subject: Re: [ammarfaizi2-block:shuah/linux-kselftest/kunit 4/16]
 lib/kunit/executor.c:78 kunit_filter_tests() warn: possible memory leak of 'copy'
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     kbuild@lists.01.org, Daniel Latypov <dlatypov@google.com>,
        kernel test robot <lkp@intel.com>, kbuild-all@lists.01.org,
        "GNU/Weeb Mailing List" <gwml@vger.gnuweeb.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Brendan Higgins <brendanhiggins@google.com>
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On Tue, Jul 12, 2022 at 8:51 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> tree:   https://github.com/ammarfaizi2/linux-block shuah/linux-kselftest/kunit
> head:   7635778bac7e46458392c1261e3916e8e9e86860
> commit: d2fbdde838f270377de4fc20e919aac3941ea55f [4/16] kunit: use kmemdup in kunit_filter_tests(), take suite as const
> config: arc-randconfig-m031-20220707 (https://download.01.org/0day-ci/archive/20220710/202207101328.ASjx88yj-lkp@intel.com/config)
> compiler: arc-elf-gcc (GCC) 11.3.0
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> smatch warnings:
> lib/kunit/executor.c:78 kunit_filter_tests() warn: possible memory leak of 'copy'
>
> vim +/copy +78 lib/kunit/executor.c

Thanks: clang-analyzer also picked this up here:
https://lore.kernel.org/all/c8073b8e-7b9e-0830-4177-87c12f16349c@intel.com/

(... snip ...)

> a127b154a8f2317 Daniel Latypov 2021-09-14  76   filtered = kcalloc(n + 1, sizeof(*filtered), GFP_KERNEL);
> a02353f491622e4 Daniel Latypov 2022-05-11  77   if (!filtered)
> a02353f491622e4 Daniel Latypov 2022-05-11 @78           return ERR_PTR(-ENOMEM);
>
> kfree(copy)?  Is the burden of random devs looking at this warning
> forever more than the burden of adding a kfree()?  Hard to measure.
>

I mean, it's the burden of not only adding a kfree(), but also a
couple of {}s. :-)

Regardless, this patch should add them:
https://lore.kernel.org/linux-kselftest/20220712095627.1770312-1-davidgow@google.com/

> a127b154a8f2317 Daniel Latypov 2021-09-14  79
> a127b154a8f2317 Daniel Latypov 2021-09-14  80   n = 0;
> a127b154a8f2317 Daniel Latypov 2021-09-14  81   kunit_suite_for_each_test_case(suite, test_case) {
> a127b154a8f2317 Daniel Latypov 2021-09-14  82           if (!test_glob || glob_match(test_glob, test_case->name))
> a127b154a8f2317 Daniel Latypov 2021-09-14  83                   filtered[n++] = *test_case;
> a127b154a8f2317 Daniel Latypov 2021-09-14  84   }
> a127b154a8f2317 Daniel Latypov 2021-09-14  85
> a127b154a8f2317 Daniel Latypov 2021-09-14  86   copy->test_cases = filtered;
> a127b154a8f2317 Daniel Latypov 2021-09-14  87   return copy;
> a127b154a8f2317 Daniel Latypov 2021-09-14  88  }
>

Cheers,
-- David