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| author | Tobin C. Harding <me@tobin.cc> | 2018-06-22 09:15:34 +1000 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2018-07-17 21:32:48 -0400 |
| commit | 3672476edaa0660eb833f54fa9edeb505417b75c (patch) | |
| tree | d60f9e1875ca9fe64a831be8ec83bebcc416257a /Documentation/admin-guide/kernel-parameters.txt | |
| parent | 1c4facb846c7f863bc65483394e80acdbacf671b (diff) | |
| download | lwn-3672476edaa0660eb833f54fa9edeb505417b75c.tar.gz lwn-3672476edaa0660eb833f54fa9edeb505417b75c.zip | |
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) <rostedt@goodmis.org>
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 8 |
1 files changed, 8 insertions, 0 deletions
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> |