Re: [PATCH v5 14/15] mm/kasan: add document into kernel-parameters.txt

Baoquan He
2026-03-17T03:36:55Z

On 03/12/26 at 07:53am, Samuel Holland wrote:
> Hi Baoquan,
>
> On 2026-02-25 2:14 AM, Baoquan He wrote:
> > And also remove the relevant description in dev-tools/kasan.rst
> > which is hw_tags specificially.
> >
> > Signed-off-by: Baoquan He <bhe@redhat.com>
> > ---
> > Documentation/admin-guide/kernel-parameters.txt | 4 ++++
> > Documentation/dev-tools/kasan.rst | 2 --
> > 2 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index cb850e5290c2..e0115fad9e60 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -2899,6 +2899,10 @@ Kernel parameters
> > js= [HW,JOY] Analog joystick
> > See Documentation/input/joydev/joystick.rst.
> >
> > + kasan= [KNL] controls whether KASAN is enabled.
> > + Format: off | on
> > + default: on
> > +
> > kasan_multi_shot
> > [KNL] Enforce KASAN (Kernel Address Sanitizer) to print
> > report on every invalid memory access. Without this
> > diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
> > index a034700da7c4..eaae83fcb5e4 100644
> > --- a/Documentation/dev-tools/kasan.rst
> > +++ b/Documentation/dev-tools/kasan.rst
> > @@ -129,8 +129,6 @@ Hardware Tag-Based KASAN mode is intended for use in production as a security
> > mitigation. Therefore, it supports additional boot parameters that allow
> > disabling KASAN altogether or controlling its features:
>
> The sentence above is now incorrect as well. I would recommend documenting the
> parameter earlier in the "Boot parameters" section instead of removing it from
> this document entirely.

Good catch and the suggestion is good to me. Thanks.

Is below change OK to you?

From 317be48b9c1bf9d33b8d8fff5e401e3155531d81 Mon Sep 17 00:00:00 2001
From: Baoquan He <bhe@redhat.com>
Date: Tue, 17 Mar 2026 11:28:39 +0800
Subject: [PATCH] mm/kasan: adjust documentation
Content-type: text/plain

To reflect the change of kasan=on|off.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
Documentation/dev-tools/kasan.rst | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index a034700da7c4..8e65bc04dbcd 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -103,6 +103,9 @@ Boot parameters
KASAN is affected by the generic ``panic_on_warn`` command line parameter.
When it is enabled, KASAN panics the kernel after printing a bug report.

+The generic ``kasan=off`` or ``=on`` command line parameter controls
+whether KASAN is enabled (default: ``on``).
+
By default, KASAN prints a bug report only for the first invalid memory access.
With ``kasan_multi_shot``, KASAN prints a report on every invalid access. This
effectively disables ``panic_on_warn`` for KASAN reports.
@@ -127,9 +130,7 @@ modes below) support altering stack trace collection behavior:

Hardware Tag-Based KASAN mode is intended for use in production as a security
mitigation. Therefore, it supports additional boot parameters that allow
-disabling KASAN altogether or controlling its features:
-
-- ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``).
+controlling its features:

- ``kasan.mode=sync``, ``=async`` or ``=asymm`` controls whether KASAN
is configured in synchronous, asynchronous or asymmetric mode of
--
2.52.0