The patch titled
Subject: kasan: docs: clean up sections
has been added to the -mm tree. Its filename is
kasan-docs-clean-up-sections.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-docs-clean-up-sections.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-docs-clean-up-sections.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: docs: clean up sections
Update KASAN documentation:
- Give some sections clearer names.
- Remove unneeded subsections in the "Tests" section.
- Move the "For developers" section and split into subsections.
Link: https://lkml.kernel.org/r/c2bbb56eaea80ad484f0ee85bb71959a3a63f1d7.1615559068.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/dev-tools/kasan.rst | 54 ++++++++++++++--------------
1 file changed, 27 insertions(+), 27 deletions(-)
--- a/Documentation/dev-tools/kasan.rst~kasan-docs-clean-up-sections
+++ a/Documentation/dev-tools/kasan.rst
@@ -168,24 +168,6 @@ particular KASAN features.
report or also panic the kernel (default: ``report``). Note, that tag
checking gets disabled after the first reported bug.
-For developers
-~~~~~~~~~~~~~~
-
-Software KASAN modes use compiler instrumentation to insert validity checks.
-Such instrumentation might be incompatible with some part of the kernel, and
-therefore needs to be disabled. To disable instrumentation for specific files
-or directories, add a line similar to the following to the respective kernel
-Makefile:
-
-- For a single file (e.g. main.o)::
-
- KASAN_SANITIZE_main.o := n
-
-- For all files in one directory::
-
- KASAN_SANITIZE := n
-
-
Implementation details
----------------------
@@ -299,8 +281,8 @@ support MTE (but supports TBI).
Hardware tag-based KASAN only reports the first found bug. After that MTE tag
checking gets disabled.
-What memory accesses are sanitised by KASAN?
---------------------------------------------
+Shadow memory
+-------------
The kernel maps memory in a number of different parts of the address
space. This poses something of a problem for KASAN, which requires
@@ -311,8 +293,8 @@ The range of kernel virtual addresses is
real memory to support a real shadow region for every address that
could be accessed by the kernel.
-By default
-~~~~~~~~~~
+Default behaviour
+~~~~~~~~~~~~~~~~~
By default, architectures only map real memory over the shadow region
for the linear mapping (and potentially other small areas). For all
@@ -362,8 +344,29 @@ unmapped. This will require changes in a
This allows ``VMAP_STACK`` support on x86, and can simplify support of
architectures that do not have a fixed module region.
-CONFIG_KASAN_KUNIT_TEST and CONFIG_KASAN_MODULE_TEST
-----------------------------------------------------
+For developers
+--------------
+
+Ignoring accesses
+~~~~~~~~~~~~~~~~~
+
+Software KASAN modes use compiler instrumentation to insert validity checks.
+Such instrumentation might be incompatible with some part of the kernel, and
+therefore needs to be disabled. To disable instrumentation for specific files
+or directories, add a line similar to the following to the respective kernel
+Makefile:
+
+- For a single file (e.g. main.o)::
+
+ KASAN_SANITIZE_main.o := n
+
+- For all files in one directory::
+
+ KASAN_SANITIZE := n
+
+
+Tests
+~~~~~
KASAN tests consist of two parts:
@@ -409,21 +412,18 @@ Or, if one of the tests failed::
There are a few ways to run KUnit-compatible KASAN tests.
1. Loadable module
-~~~~~~~~~~~~~~~~~~
With ``CONFIG_KUNIT`` enabled, ``CONFIG_KASAN_KUNIT_TEST`` can be built as
a loadable module and run on any architecture that supports KASAN by loading
the module with insmod or modprobe. The module is called ``test_kasan``.
2. Built-In
-~~~~~~~~~~~
With ``CONFIG_KUNIT`` built-in, ``CONFIG_KASAN_KUNIT_TEST`` can be built-in
on any architecure that supports KASAN. These and any other KUnit tests enabled
will run and print the results at boot as a late-init call.
3. Using kunit_tool
-~~~~~~~~~~~~~~~~~~~
With ``CONFIG_KUNIT`` and ``CONFIG_KASAN_KUNIT_TEST`` built-in, it's also
possible use ``kunit_tool`` to see the results of these and other KUnit tests
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-mm-fix-crash-with-hw_tags-and-debug_pagealloc.patch
kasan-fix-kasan_stack-dependency-for-hw_tags.patch
kasan-fix-per-page-tags-for-non-page_alloc-pages.patch
kasan-initialize-shadow-to-tag_invalid-for-sw_tags.patch
mm-kasan-dont-poison-boot-memory-with-tag-based-modes.patch
arm64-kasan-allow-to-init-memory-when-setting-tags.patch
kasan-init-memory-in-kasan_unpoison-for-hw_tags.patch
kasan-mm-integrate-page_alloc-init-with-hw_tags.patch
kasan-mm-integrate-slab-init_on_alloc-with-hw_tags.patch
kasan-mm-integrate-slab-init_on_free-with-hw_tags.patch
kasan-docs-clean-up-sections.patch
kasan-docs-update-overview-section.patch
kasan-docs-update-usage-section.patch
kasan-docs-update-error-reports-section.patch
kasan-docs-update-boot-parameters-section.patch
kasan-docs-update-generic-implementation-details-section.patch
kasan-docs-update-sw_tags-implementation-details-section.patch
kasan-docs-update-hw_tags-implementation-details-section.patch
kasan-docs-update-shadow-memory-section.patch
kasan-docs-update-ignoring-accesses-section.patch
kasan-docs-update-tests-section.patch
