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| author | Marc Herbert <marc.herbert@linux.intel.com> | 2026-01-07 20:21:32 +0000 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2026-01-16 11:31:58 -0700 |
| commit | d9d25684e98d45322a9b7ff44beb4275ffdf1d74 (patch) | |
| tree | e3d24d17177e05eb060f798fcec3a8fdd7872524 | |
| parent | 653793b8a3e502fe379daef5995d5a052fb1b04f (diff) | |
docs: make kptr_restrict and hash_pointers reference each other
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>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260107-doc-hash-ptr-v2-1-cb4c161218d7@linux.intel.com>
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 3 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f4a2bf906bf3..8e3738d9588a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1969,6 +1969,9 @@ Kernel parameters param "no_hash_pointers" is an alias for this mode. + For controlling hashing dynamically at runtime, + use the "kernel.kptr_restrict" sysctl 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 239da22c4e28..0315eb7ee6d4 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -591,6 +591,9 @@ 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. + softlockup_sys_info & hardlockup_sys_info ========================================= A comma separated list of extra system information to be dumped when |