Commit d9d25684 authored by Marc Herbert's avatar Marc Herbert Committed by Jonathan Corbet
Browse files

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: default avatarMarc Herbert <marc.herbert@linux.intel.com>
Acked-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
Message-ID: <20260107-doc-hash-ptr-v2-1-cb4c161218d7@linux.intel.com>
parent 653793b8

Documentation/admin-guide/kernel-parameters.txt

+3 −0
Original line number Diff line number Diff line
@@ -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.

Documentation/admin-guide/sysctl/kernel.rst

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Original line number Diff line number Diff line
@@ -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