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Message-ID: <99096ca9-f43b-471e-9a8f-cdd4adf93fba@collabora.com>
Date: Fri, 3 May 2024 22:18:18 +0500
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Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>,
 Andrei Vagin <avagin@openvz.org>, Andrei Vagin <avagin@gmail.com>,
 Dmitry Safonov <dima@arista.com>, Thomas Gleixner <tglx@linutronix.de>,
 Valentin Obst <kernel@valentinobst.de>, linux-kselftest@vger.kernel.org,
 LKML <linux-kernel@vger.kernel.org>, llvm@lists.linux.dev
Subject: Re: [PATCH] selftest/timerns: fix clang build failures for abs()
 calls
To: John Hubbard <jhubbard@nvidia.com>, Shuah Khan <shuah@kernel.org>
References: <20240503032956.89290-1-jhubbard@nvidia.com>
Content-Language: en-US
From: Muhammad Usama Anjum <usama.anjum@collabora.com>
In-Reply-To: <20240503032956.89290-1-jhubbard@nvidia.com>
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On 5/3/24 8:29 AM, John Hubbard wrote:
> First of all, in order to build with clang at all, one must first apply
> Valentin Obst's build fix for LLVM [1]. Once that is done, then when
> building with clang, via:
> 
>     make LLVM=1 -C tools/testing/selftests
> 
> ...then clang warns about mismatches between the expected and required
> integer length being supplied to abs(3).
> 
> Fix this by using the correct variant of abs(3): labs(3) or llabs(3), in
> these cases.
> 
> [1] https://lore.kernel.org/all/20240329-selftests-libmk-llvm-rfc-v1-1-2f9ed7d1c49f@valentinobst.de/
> 
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Thanks for fixing!
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>

> ---
>  tools/testing/selftests/timens/exec.c       | 6 +++---
>  tools/testing/selftests/timens/timer.c      | 2 +-
>  tools/testing/selftests/timens/timerfd.c    | 2 +-
>  tools/testing/selftests/timens/vfork_exec.c | 4 ++--
>  4 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/testing/selftests/timens/exec.c b/tools/testing/selftests/timens/exec.c
> index e40dc5be2f66..d12ff955de0d 100644
> --- a/tools/testing/selftests/timens/exec.c
> +++ b/tools/testing/selftests/timens/exec.c
> @@ -30,7 +30,7 @@ int main(int argc, char *argv[])
>  
>  		for (i = 0; i < 2; i++) {
>  			_gettime(CLOCK_MONOTONIC, &tst, i);
> -			if (abs(tst.tv_sec - now.tv_sec) > 5)
> +			if (labs(tst.tv_sec - now.tv_sec) > 5)
>  				return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec);
>  		}
>  		return 0;
> @@ -50,7 +50,7 @@ int main(int argc, char *argv[])
>  
>  	for (i = 0; i < 2; i++) {
>  		_gettime(CLOCK_MONOTONIC, &tst, i);
> -		if (abs(tst.tv_sec - now.tv_sec) > 5)
> +		if (labs(tst.tv_sec - now.tv_sec) > 5)
>  			return pr_fail("%ld %ld\n",
>  					now.tv_sec, tst.tv_sec);
>  	}
> @@ -70,7 +70,7 @@ int main(int argc, char *argv[])
>  		/* Check that a child process is in the new timens. */
>  		for (i = 0; i < 2; i++) {
>  			_gettime(CLOCK_MONOTONIC, &tst, i);
> -			if (abs(tst.tv_sec - now.tv_sec - OFFSET) > 5)
> +			if (labs(tst.tv_sec - now.tv_sec - OFFSET) > 5)
>  				return pr_fail("%ld %ld\n",
>  						now.tv_sec + OFFSET, tst.tv_sec);
>  		}
> diff --git a/tools/testing/selftests/timens/timer.c b/tools/testing/selftests/timens/timer.c
> index 5e7f0051bd7b..5b939f59dfa4 100644
> --- a/tools/testing/selftests/timens/timer.c
> +++ b/tools/testing/selftests/timens/timer.c
> @@ -56,7 +56,7 @@ int run_test(int clockid, struct timespec now)
>  			return pr_perror("timerfd_gettime");
>  
>  		elapsed = new_value.it_value.tv_sec;
> -		if (abs(elapsed - 3600) > 60) {
> +		if (llabs(elapsed - 3600) > 60) {
>  			ksft_test_result_fail("clockid: %d elapsed: %lld\n",
>  					      clockid, elapsed);
>  			return 1;
> diff --git a/tools/testing/selftests/timens/timerfd.c b/tools/testing/selftests/timens/timerfd.c
> index 9edd43d6b2c1..a4196bbd6e33 100644
> --- a/tools/testing/selftests/timens/timerfd.c
> +++ b/tools/testing/selftests/timens/timerfd.c
> @@ -61,7 +61,7 @@ int run_test(int clockid, struct timespec now)
>  			return pr_perror("timerfd_gettime(%d)", clockid);
>  
>  		elapsed = new_value.it_value.tv_sec;
> -		if (abs(elapsed - 3600) > 60) {
> +		if (llabs(elapsed - 3600) > 60) {
>  			ksft_test_result_fail("clockid: %d elapsed: %lld\n",
>  					      clockid, elapsed);
>  			return 1;
> diff --git a/tools/testing/selftests/timens/vfork_exec.c b/tools/testing/selftests/timens/vfork_exec.c
> index beb7614941fb..5b8907bf451d 100644
> --- a/tools/testing/selftests/timens/vfork_exec.c
> +++ b/tools/testing/selftests/timens/vfork_exec.c
> @@ -32,7 +32,7 @@ static void *tcheck(void *_args)
>  
>  	for (i = 0; i < 2; i++) {
>  		_gettime(CLOCK_MONOTONIC, &tst, i);
> -		if (abs(tst.tv_sec - now->tv_sec) > 5) {
> +		if (labs(tst.tv_sec - now->tv_sec) > 5) {
>  			pr_fail("%s: in-thread: unexpected value: %ld (%ld)\n",
>  				args->tst_name, tst.tv_sec, now->tv_sec);
>  			return (void *)1UL;
> @@ -64,7 +64,7 @@ static int check(char *tst_name, struct timespec *now)
>  
>  	for (i = 0; i < 2; i++) {
>  		_gettime(CLOCK_MONOTONIC, &tst, i);
> -		if (abs(tst.tv_sec - now->tv_sec) > 5)
> +		if (labs(tst.tv_sec - now->tv_sec) > 5)
>  			return pr_fail("%s: unexpected value: %ld (%ld)\n",
>  					tst_name, tst.tv_sec, now->tv_sec);
>  	}
> 
> base-commit: f03359bca01bf4372cf2c118cd9a987a5951b1c8
> prerequisite-patch-id: b901ece2a5b78503e2fb5480f20e304d36a0ea27

-- 
BR,
Muhammad Usama Anjum