linux-kernel - Re: [PATCH] selftests: kvm: fix mismatched fclose() after popen()

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Date:   Thu, 21 Oct 2021 11:55:29 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     pbonzini@...hat.com, shuah@...nel.org
Cc:     kvm@...r.kernel.org, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH] selftests: kvm: fix mismatched fclose() after popen()

On 10/21/21 11:53 AM, Shuah Khan wrote:
> get_warnings_count() foes fclose() using File * returned from popen().

Oops should have been "does". Sending v2 with that change now.

> Fix it to call pclose() as it should.
> 
> tools/testing/selftests/kvm/x86_64/mmio_warning_test
> x86_64/mmio_warning_test.c: In function ‘get_warnings_count’:
> x86_64/mmio_warning_test.c:87:9: warning: ‘fclose’ called on pointer returned from a mismatched allocation function [-Wmismatched-dealloc]
>     87 |         fclose(f);
>        |         ^~~~~~~~~
> x86_64/mmio_warning_test.c:84:13: note: returned from ‘popen’
>     84 |         f = popen("dmesg | grep \"WARNING:\" | wc -l", "r");
>        |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Signed-off-by: Shuah Khan <skhan@...uxfoundation.org>
> ---
>   tools/testing/selftests/kvm/x86_64/mmio_warning_test.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c b/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c
> index 8039e1eff938..9f55ccd169a1 100644
> --- a/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c
> @@ -84,7 +84,7 @@ int get_warnings_count(void)
>   	f = popen("dmesg | grep \"WARNING:\" | wc -l", "r");
>   	if (fscanf(f, "%d", &warnings) < 1)
>   		warnings = 0;
> -	fclose(f);
> +	pclose(f);
>   
>   	return warnings;
>   }
> 

thanks,
-- Shuah