Commit f3590747 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds

kasan: docs: update boot parameters section

Update the "Boot parameters" section in KASAN documentation:

 - Mention panic_on_warn.

 - Mention kasan_multi_shot and its interaction with panic_on_warn.

 - Clarify kasan.fault=panic interaction with panic_on_warn.

 - A readability clean-up.

Link: https://lkml.kernel.org/r/01364952f15789948f0627d6733b5cdf5209f83a.1615559068.git.andreyknvl@google.comSigned-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 836f79a2
...@@ -174,10 +174,16 @@ call_rcu() and workqueue queuing. ...@@ -174,10 +174,16 @@ call_rcu() and workqueue queuing.
Boot parameters 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.
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.
Hardware tag-based KASAN mode (see the section about various modes below) is Hardware tag-based KASAN mode (see the section about various modes below) is
intended for use in production as a security mitigation. Therefore, it supports intended for use in production as a security mitigation. Therefore, it supports
boot parameters that allow to disable KASAN competely or otherwise control boot parameters that allow disabling KASAN or controlling its features.
particular KASAN features.
- ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``). - ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``).
...@@ -194,8 +200,8 @@ particular KASAN features. ...@@ -194,8 +200,8 @@ particular KASAN features.
traces collection (default: ``on``). traces collection (default: ``on``).
- ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN - ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN
report or also panic the kernel (default: ``report``). Note, that tag report or also panic the kernel (default: ``report``). The panic happens even
checking gets disabled after the first reported bug. if ``kasan_multi_shot`` is enabled.
Implementation details Implementation details
---------------------- ----------------------
......
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