vsprintf.c uses a mix of the `kernel.kptr_restrict` sysctl and the
`hash_pointers` boot param to control pointer hashing. But that wasn't
possible to tell without looking at the source code.
They have a different focus and purpose. To avoid wasting the time of
users trying to use one instead of the other, simply have them reference
each other in the Documentation.
Signed-off-by: Marc Herbert <marc.herbert@linux.intel.com>
---
(please just go ahead with any minor corrections; I mean do not ask
for my opinion)
---
Documentation/admin-guide/kernel-parameters.txt | 3 +++
Documentation/admin-guide/sysctl/kernel.rst | 2 ++
2 files changed, 5 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6c42061ca20e..b4305fa17a19 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1867,6 +1867,9 @@
param "no_hash_pointers" is an alias for
this mode.
+ For controlling hashing dynamically at runtime,
+ use the sysctl `kernel.kptr_restrict` instead.
+
hashdist= [KNL,NUMA] Large hashes allocated during boot
are distributed across NUMA nodes. Defaults on
for 64-bit NUMA, off otherwise.
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index f3ee807b5d8b..8833e1364ab9 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -576,6 +576,8 @@ if leaking kernel pointer values to unprivileged users is a concern.
When ``kptr_restrict`` is set to 2, kernel pointers printed using
%pK will be replaced with 0s regardless of privileges.
+For disabling these security restrictions early at boot time (and once
+for all), use the ``hash_pointers`` boot parameter instead.
modprobe
========
---
base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449
change-id: 20251204-doc-hash-ptr-00e46e1a5398
Best regards,
--
Marc Herbert <marc.herbert@linux.intel.com>