From 3672476edaa0660eb833f54fa9edeb505417b75c Mon Sep 17 00:00:00 2001 From: "Tobin C. Harding" Date: Fri, 22 Jun 2018 09:15:34 +1000 Subject: vsprintf: Add command line option debug_boot_weak_hash 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. Reviewed-by: Steven Rostedt (VMware) Signed-off-by: Tobin C. Harding Signed-off-by: Theodore Ts'o --- Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index efc7aa7a0670..0c8f7889efa1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -748,6 +748,14 @@ debug [KNL] Enable kernel debugging (events log level). + debug_boot_weak_hash + [KNL] Enable printing [hashed] pointers early in the + boot sequence. If enabled, we use a weak hash instead + of siphash to hash pointers. Use this option if you are + seeing instances of '(___ptrval___)') and need to see a + value (hashed pointer) instead. Cryptographically + insecure, please do not use on production kernels. + debug_locks_verbose= [KNL] verbose self-tests Format=<0|1> -- cgit