kcsan: Document static blacklisting options

Updates the section on "Selective analysis", listing all available
options to blacklist reporting data races for: specific accesses,
functions, compilation units, and entire directories.

These options should provide adequate control for maintainers to opt out
of KCSAN analysis at varying levels of granularity. It is hoped to
provide the required control to reflect preferences for handling data
races across the kernel.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Marco Elver 2019-12-12 01:07:08 +01:00 committed by Paul E. McKenney
parent 944bc9cca7
commit 7161177481
1 changed files with 17 additions and 7 deletions

View File

@ -101,18 +101,28 @@ instrumentation or e.g. DMA accesses.
Selective analysis Selective analysis
~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~
To disable KCSAN data race detection for an entire subsystem, add to the It may be desirable to disable data race detection for specific accesses,
respective ``Makefile``:: functions, compilation units, or entire subsystems. For static blacklisting,
the below options are available:
KCSAN_SANITIZE := n * KCSAN understands the ``data_race(expr)`` annotation, which tells KCSAN that
any data races due to accesses in ``expr`` should be ignored and resulting
behaviour when encountering a data race is deemed safe.
To disable KCSAN on a per-file basis, add to the ``Makefile``:: * Disabling data race detection for entire functions can be accomplished by
using the function attribute ``__no_kcsan`` (or ``__no_kcsan_or_inline`` for
``__always_inline`` functions). To dynamically control for which functions
data races are reported, see the `debugfs`_ blacklist/whitelist feature.
* To disable data race detection for a particular compilation unit, add to the
``Makefile``::
KCSAN_SANITIZE_file.o := n KCSAN_SANITIZE_file.o := n
KCSAN also understands the ``data_race(expr)`` annotation, which tells KCSAN * To disable data race detection for all compilation units listed in a
that any data races due to accesses in ``expr`` should be ignored and resulting ``Makefile``, add to the respective ``Makefile``::
behaviour when encountering a data race is deemed safe.
KCSAN_SANITIZE := n
debugfs debugfs
~~~~~~~ ~~~~~~~