Re: [PATCH v2] lib/test_printf.c: call wait_for_random_bytes() before plain %p tests

[Thierry Escande]

On 13/06/2018 18:30, Andy Shevchenko wrote:
> On Wed, Jun 13, 2018 at 5:59 PM, Thierry Escande
> <thierry.escande@xxxxxxxxxx> wrote:
> > On 13/06/2018 13:22, Andy Shevchenko wrote:
> > > On Wed, Jun 13, 2018 at 12:29 PM, Thierry Escande
> > > <thierry.escande@xxxxxxxxxx> 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.
> > > > Since we cannot wait for the crng to be initialized for an undefined
> > > > time, both plain 'p' tests now accept the string "(ptrval)" as a valid
> > > > result and print a warning message.
> > >
> > >
> > > There are two possibilities:
> > >    1. (ptrval) for 32-bit case
> > >    2. (____ptrval____) for 64-bit case.
> >
> >
> >  From lib/vsprintf.c, ptr_to_id() puts "(ptrval)" into the buffer, then it
> > gets left-padded with spaces by widen_string().
>
> Which kernel version you are trying to fix?
>
> What I see for a long time in linux-next:
>
> static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
> {
>          const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
> ...
>
> brought by the commit 91efafb1dd8f ("lib/vsprintf: Replace space with
> '_' before crng is ready").

I missed that one as it's not in v4.17. My bad.

Regards,
Thierry