On Wed, 29 Apr 2015 09:34:51 +0300
Michael Tokarev <m...@tls.msk.ru> wrote:
> 27.04.2015 19:59, Thomas Huth wrote:
> > valgrind complains here about uninitialized bytes with the following
> > message:
> >
> > ==17814== Syscall param ioctl(generic) points to uninitialised byte(s)
> > ==17814== at 0x466A780: ioctl (in /usr/lib64/power8/libc-2.17.so)
> > ==17814== by 0x100735B7: kvm_vm_ioctl (kvm-all.c:1920)
> > ==17814== by 0x10074583: kvm_set_ioeventfd_mmio (kvm-all.c:574)
> >
> > Let's fix it by using a proper struct initializer in
> > kvm_set_ioeventfd_mmio().
> >
> > Signed-off-by: Thomas Huth <th...@redhat.com>
> > ---
> > kvm-all.c | 14 +++++++-------
> > 1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/kvm-all.c b/kvm-all.c
> > index dd44f8c..077b0ed 100644
> > --- a/kvm-all.c
> > +++ b/kvm-all.c
> > @@ -552,13 +552,13 @@ static int kvm_set_ioeventfd_mmio(int fd, hwaddr
> > addr, uint32_t val,
> > bool assign, uint32_t size, bool
> > datamatch)
> > {
> > int ret;
> > - struct kvm_ioeventfd iofd;
> > -
> > - iofd.datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) :
> > 0;
> > - iofd.addr = addr;
> > - iofd.len = size;
> > - iofd.flags = 0;
> > - iofd.fd = fd;
> > + struct kvm_ioeventfd iofd = {
> > + .datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) :
> > 0,
> > + .addr = addr,
> > + .len = size,
> > + .flags = 0,
> > + .fd = fd,
> > + };
>
> Hm. So, what's the difference? The same fields are assigned the same
> values, why in first case we have some uninitialized data and in second
> case everything is initialized? Does struct initializer zero-fills all
> other places (alignments, missing fields etc) ?
Right, the struct initializer fills the remaining fields with zeros.
> If yes, there's no need to assign zero to flags, btw ;)
True. Shall I sent a patch without that line?
Thomas
