On Wed, Dec 16, 2020 at 09:33:43AM +0100, Otto Moerbeek wrote:
> 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.
As far as I can see, the error is reported every time the value
returned by TIB_GET() is used. In the case of write(2) that is via
the ENTER_CANCEL_POINT and LEAVE_CANCEL_POINT macros.
I have no clue how to fix this yet.
>
> -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
>
