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