[LTP] [PATCH v3 3/3] syscalls/ioctl_ns0[156]: align stack and wait for child

[Li Wang]

On Thu, Jun 13, 2019 at 6:16 PM Jan Stancek <jstancek@redhat.com> wrote:

>
>
> ----- Original Message -----
> > On Thu, Jun 13, 2019 at 3:25 PM Jan Stancek <jstancek@redhat.com> wrote:
> >
> > > Test crashes (SIGBUS) when using child stack have been observed for
> > > ioctl_ns01. This is because stack isn't aligned. Use ltp_alloc_stack()
> > > for stack allocation.
> > >
> > > Add SIGCHLD to clone flags, so that LTP library can reap all children
> > > and check their return code.  Also check ltp_clone() return value.
> > >
> > > Suppress warning for unused *arg in child().
> > >
> > > Signed-off-by: Jan Stancek <jstancek@redhat.com>
> > > ---
> > >  testcases/kernel/syscalls/ioctl/ioctl_ns01.c | 13 +++++++++----
> > >  testcases/kernel/syscalls/ioctl/ioctl_ns05.c | 12 +++++++++---
> > >  testcases/kernel/syscalls/ioctl/ioctl_ns06.c | 15 +++++++++++----
> > >  3 files changed, 29 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/testcases/kernel/syscalls/ioctl/ioctl_ns01.c
> > > b/testcases/kernel/syscalls/ioctl/ioctl_ns01.c
> > > index dfde4da6c5d6..d241a5d0fa53 100644
> > > --- a/testcases/kernel/syscalls/ioctl/ioctl_ns01.c
> > > +++ b/testcases/kernel/syscalls/ioctl/ioctl_ns01.c
> > > @@ -23,7 +23,7 @@
> > >
> > >  #define STACK_SIZE (1024 * 1024)
> > >
> > > -static char child_stack[STACK_SIZE];
> > > +static char *child_stack;
> > >
> > >  static void setup(void)
> > >  {
> > > @@ -31,6 +31,10 @@ static void setup(void)
> > >
> > >         if (exists < 0)
> > >                 tst_res(TCONF, "namespace not available");
> > > +
> > > +       child_stack = ltp_alloc_stack(STACK_SIZE);
> > >
> >
> > As you commented that "User is responsible for freeing allocated memory",
> > but you forget to do that in each of these test cases :).
>
> I omitted it on purpose. OS will clean it up on exit, since it's called
> only in setup() it's not going to keep leaking more memory.
>

Okay. I believe that, but it is not a recommended coding habit which I had
been told ;-).


>
> >
> > We need free(child_stack) in the cleanup function.
>
> Can you elaborate?
>

Nothing else. It is just a supplementary as above comment. If we do memory
release, then add:

static void cleanup(viod)
{
    if (child_stack)
        free(child_stack);
}

-- 
Regards,
Li Wang
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linux.it/pipermail/ltp/attachments/20190613/cb918bd1/attachment.html>