Commit 1ead009c authored by Jonathan Corbet's avatar Jonathan Corbet

docs: sphinxify ubsan.txt and move it to dev-tools

Acked-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 2757aafa
......@@ -19,3 +19,4 @@ whole; patches welcome!
kcov
gcov
kasan
ubsan
Undefined Behavior Sanitizer - UBSAN
Overview
--------
The Undefined Behavior Sanitizer - UBSAN
========================================
UBSAN is a runtime undefined behaviour checker.
......@@ -10,11 +8,13 @@ Compiler inserts code that perform certain kinds of checks before operations
that may cause UB. If check fails (i.e. UB detected) __ubsan_handle_*
function called to print error message.
GCC has that feature since 4.9.x [1] (see -fsanitize=undefined option and
its suboptions). GCC 5.x has more checkers implemented [2].
GCC has that feature since 4.9.x [1_] (see ``-fsanitize=undefined`` option and
its suboptions). GCC 5.x has more checkers implemented [2_].
Report example
---------------
--------------
::
================================================================================
UBSAN: Undefined behaviour in ../include/linux/bitops.h:110:33
......@@ -47,29 +47,33 @@ Report example
Usage
-----
To enable UBSAN configure kernel with:
To enable UBSAN configure kernel with::
CONFIG_UBSAN=y
and to check the entire kernel:
and to check the entire kernel::
CONFIG_UBSAN_SANITIZE_ALL=y
To enable 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):
UBSAN_SANITIZE_main.o := y
- For a single file (e.g. main.o)::
UBSAN_SANITIZE_main.o := y
For all files in one directory:
UBSAN_SANITIZE := y
- For all files in one directory::
UBSAN_SANITIZE := y
To exclude files from being instrumented even if
CONFIG_UBSAN_SANITIZE_ALL=y, use:
``CONFIG_UBSAN_SANITIZE_ALL=y``, use::
UBSAN_SANITIZE_main.o := n
and::
UBSAN_SANITIZE_main.o := n
and:
UBSAN_SANITIZE := n
UBSAN_SANITIZE := n
Detection of unaligned accesses controlled through the separate option -
CONFIG_UBSAN_ALIGNMENT. It's off by default on architectures that support
......@@ -80,5 +84,5 @@ reports.
References
----------
[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
.. _1: https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
.. _2: https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
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