On Wed, Nov 10, 2021 at 10:04 AM Anders Roxell <anders.roxell@xxxxxxxxxx> wrote:
>
> When building selftests/timens with clang, the compiler warn about the
> function abs() see below:
>
> exec.c:33:8: error: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Werror,-Wabsolute-value]
> if (abs(tst.tv_sec - now.tv_sec) > 5)
> ^
> exec.c:33:8: note: use function 'labs' instead
> if (abs(tst.tv_sec - now.tv_sec) > 5)
> ^~~
> labs
>
> Rework to store the time difference in a 'long long' and pass that to
> llabs(), since the variable can be an 'int', 'long' or 'long long'
> depending on the architecture and C library.
>
> Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
> tools/testing/selftests/timens/exec.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/timens/exec.c b/tools/testing/selftests/timens/exec.c
> index e40dc5be2f66..04439e6ac8a2 100644
> --- a/tools/testing/selftests/timens/exec.c
> +++ b/tools/testing/selftests/timens/exec.c
> @@ -21,6 +21,7 @@
> int main(int argc, char *argv[])
> {
> struct timespec now, tst;
> + long long timediff;
> int status, i;
> pid_t pid;
>
> @@ -30,7 +31,8 @@ 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)
> + timediff = tst.tv_sec - now.tv_sec;
> + if (llabs(timediff) > 5)
> return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec);
> }
> return 0;
> @@ -50,7 +52,8 @@ 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)
> + timediff = tst.tv_sec - now.tv_sec;
> + if (llabs(timediff) > 5)
> return pr_fail("%ld %ld\n",
> now.tv_sec, tst.tv_sec);
> }
> @@ -70,7 +73,8 @@ 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)
> + timediff = tst.tv_sec - now.tv_sec - OFFSET;
> + if (llabs(timediff) > 5)
> return pr_fail("%ld %ld\n",
> now.tv_sec + OFFSET, tst.tv_sec);
> }
> --
> 2.33.0
>
--
Thanks,
~Nick Desaulniers
