On Thu, Jun 07, 2018 at 02:24:34PM +0200, Petr Mladek wrote:
> On Mon 2018-06-04 13:37:08, Thierry Escande wrote:
> > If the test_printf module is loaded before the crng is initialized, the
> > plain 'p' tests will fail because the printed address will not be hashed
> > and the buffer will contain '(ptrval)' instead.
> > This patch adds a call to wait_for_random_bytes() before plain 'p' tests
> > to make sure the crng is initialized.
>
> Hmm, my system did not boot with this patch and
> CONFIG_TEST_PRINTF=y
And neither does my test box. It killed my tests I was running, as one of the
configs I test has this set.
It appears that Andrew pulled it in and sent it to Linus, as it is in
4.18-rc1, and I need to now revert this patch to make my tests work.
-- Steve
>
> I guess that there was not enough entropy. It is basically a deadlock.
> The build-in module init calls are called when SMP is enabled but
> there is no real activity and the init calls are called sequentially.
> Therefore there is nothing that could produce some entropy, ...
>
> I suggest to skip the test when crng is not ready.
>
> Best Regards,
> Petr
>
> > Signed-off-by: Thierry Escande <thierry.esca...@linaro.org>
> > Acked-by: Tobin C. Harding <m...@tobin.cc>
> > ---
> > lib/test_printf.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/lib/test_printf.c b/lib/test_printf.c
> > index 71ebfa43ad05..839be9385a8a 100644
> > --- a/lib/test_printf.c
> > +++ b/lib/test_printf.c
> > @@ -260,6 +260,13 @@ plain(void)
> > {
> > int err;
> >
> > + /*
> > + * Make sure crng is ready. Otherwise we get "(ptrval)" instead
> > + * of a hashed address when printing '%p' in plain_hash() and
> > + * plain_format().
> > + */
> > + wait_for_random_bytes();
> > +
> > err = plain_hash();
> > if (err) {
> > pr_warn("plain 'p' does not appear to be hashed\n");
> > --
> > 2.14.1
> >
