On Mon, Dec 14, 2020 at 02:24:52PM +0900, Masato Asou wrote:

> Hi,
> 
> From: Otto Moerbeek <o...@drijf.net>
> Date: Fri, 11 Dec 2020 08:54:36 +0100
> 
> > Hi,
> > 
> > I did some basic testing of valgrind on amd64 and it seems to be in
> > better shape than before, at least for memory leak detection.
> > 
> > But I do seem to get a report on every syscall done. One example:
> > 
> > ==7218== Use of uninitialised value of size 8
> > ==7218==    at 0x4A7670E: write (sys/w_write.c:28)
> > ==7218==    by 0x4A40F52: __sflush (stdio/fflush.c:80)
> > ==7218==    by 0x4A94726: __sfvwrite (stdio/fvwrite.c:191)
> > ==7218==    by 0x4ACCA68: __sprint (stdio/vfprintf.c:111)
> > ==7218==    by 0x4ACCA68: __vfprintf (stdio/vfprintf.c:1107)
> > ==7218==    by 0x4AC8851: vfprintf (stdio/vfprintf.c:266)
> > ==7218==    by 0x4A7C8A0: printf (stdio/printf.c:44)
> > ==7218==    by 0x109AB8: main (x.c:14)
> > 
> > Is there a way to avoid this? If so, it would be nice to mention that
> > in a pkg-readme.
> > 
> >     -Otto
> 
> Do you want somethig like this?

Thanks, that looks nice, but first I think it is good if I do an
investigation *why* this is reported.

        -Otto
        
> 
> $ cvs -q diff .
> Index: devel/valgrind/pkg-readme
> ===================================================================
> RCS file: devel/valgrind/pkg-readme
> diff -N devel/valgrind/pkg-readme
> --- /dev/null   1 Jan 1970 00:00:00 -0000
> +++ devel/valgrind/pkg-readme   14 Dec 2020 05:18:59 -0000
> @@ -0,0 +1,23 @@
> +Suppressiong errors
> +
> +If you got a report on every syscall done as followes:
> +
> +==67551== Use of uninitialised value of size 8
> +==67551==    at 0x4AC08F9: write (sys/w_write.c:26)
> +==67551==    by 0x4A5AC12: __sflush (stdio/fflush.c:80)
> +==67551==    by 0x4A4C676: __sfvwrite (stdio/fvwrite.c:191)
> +==67551==    by 0x4A80CD8: __sprint (stdio/vfprintf.c:111)
> +==67551==    by 0x4A80CD8: __vfprintf (stdio/vfprintf.c:1107)
> +==67551==    by 0x4A7CAC1: vfprintf (stdio/vfprintf.c:266)
> +==67551==    by 0x4A54680: printf (stdio/printf.c:44)
> +==67551==    by 0x109BA5: main (main.c:19)
> +
> +You can use --gen-suppressions=yes and --suppressions=FILENAME
> options of
> +valgrind.
> +
> +    $ yes | valgrind --gen-suppressions=yes ./a.out 2>supress.txt 
> +    $ sed -e '/^==.*[^{]$/d' -e 's/==.*{/{/' supress.log >
> supress.txt
> +    $ valgrind --suppressions=supress.txt ./a.out
> +
> +See also:
> +https://www.valgrind.org/docs/manual/manual-core.html#manual-core.suppress
> --
> ASOU Masato

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