On Wed, Jun 20, 2018 at 09:09:49AM -0700, Randy Dunlap wrote: > On 06/19/2018 09:20 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. > > > > Signed-off-by: Tobin C. Harding <m...@tobin.cc> > > Reviewed-by: Steven Rostedt (VMware) <rost...@goodmis.org> > > --- > > Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++ > > lib/vsprintf.c | 17 +++++++++++++++++ > > 2 files changed, 26 insertions(+) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt > > b/Documentation/admin-guide/kernel-parameters.txt > > index 638342d0a095..a116fc0366b0 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -748,6 +748,15 @@ > > > > debug [KNL] Enable kernel debugging (events log level). > > > > + debug_boot_weak_hash > > + [KNL] Enable printing pointers early in the boot > > + sequence. If enabled, we use a weak hash instead of > > + siphash to hash pointers. Use this option if you need > > + to see pointer values during early boot (i.e you are > > maybe: > to see hashed pointer values > i.e., not raw pointers.
You cannot see 'raw pointers' anyways? > > > + seeing instances of '(___ptrval___)'). > > + Cryptographically insecure, please do not use on > > + production kernels. thanks for the review, I don't quiet see how to use your suggestion to make the text clearer. If you still feel this change is needed perhaps you could write so I understand i.e 'Use this option if ...' thanks, Tobin.
