Re: [PATCH v6 4/4] vsprintf: Add command line option debug_boot_weak_hash

Tobin C. Harding
2018-05-30T04:27:50Z

On Mon, May 28, 2018 at 10:40:43AM -0700, Randy Dunlap wrote:
> On 05/27/2018 06:46 PM, Tobin C. Harding wrote:
> > Currently printing [hashed] pointers requires enough entropy to be
> > available. Early in the boot sequence this may not be the case
> > resulting in a dummy string '(____ptrval____)' being printed. This
> > makes debugging the early boot sequence difficult. We can relax the
> > requirement to use cryptographically secure hashing during debugging.
> > This enables debugging while keeping development/production kernel
> > behaviour the same.
> >
> > If new command line option debug_boot_weak_hash is enabled use
> > cryptographically insecure hashing and hash pointer value immediately.
> >
> > Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
> > Cc: Steven Rostedt <rostedt@goodmis.org>
> > Cc: Randy Dunlap <rdunlap@infradead.org>
> > Signed-off-by: Tobin C. Harding <me@tobin.cc>
> > ---
> > Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++
> > lib/vsprintf.c | 20 ++++++++++++++++++++
> > 2 files changed, 29 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index f2040d46f095..8a86d895343e 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -753,6 +753,15 @@
> >
> > debug [KNL] Enable kernel debugging (events log level).
> >
>
> Hi,
> This is much more readable than the previous version. Thanks.

Thanks for following up with this one Randy.

Tobin