The following commit has been merged into the locking/debug branch of tip: Commit-ID: e675d2533a74acfa95c62e7bb088335866f44fd2 Gitweb: https://git.kernel.org/tip/e675d2533a74acfa95c62e7bb088335866f44fd2 Author: Marco Elver <elver@xxxxxxxxxx> AuthorDate: Mon, 07 Jun 2021 14:56:49 +02:00 Committer: Paul E. McKenney <paulmck@xxxxxxxxxx> CommitterDate: Tue, 20 Jul 2021 13:49:43 -07:00 kcsan: Introduce CONFIG_KCSAN_STRICT Add a simpler Kconfig variable to configure KCSAN's "strict" mode. This makes it simpler in documentation or messages to suggest just a single configuration option to select the strictest checking mode (vs. currently having to list several options). Signed-off-by: Marco Elver <elver@xxxxxxxxxx> Acked-by: Mark Rutland <mark.rutland@xxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- Documentation/dev-tools/kcsan.rst | 4 ++++ lib/Kconfig.kcsan | 10 ++++++++++ 2 files changed, 14 insertions(+) diff --git a/Documentation/dev-tools/kcsan.rst b/Documentation/dev-tools/kcsan.rst index 6a600cf..69dc9c5 100644 --- a/Documentation/dev-tools/kcsan.rst +++ b/Documentation/dev-tools/kcsan.rst @@ -127,6 +127,10 @@ Kconfig options: causes KCSAN to not report data races due to conflicts where the only plain accesses are aligned writes up to word size. +To use the strictest possible rules, select ``CONFIG_KCSAN_STRICT=y``, which +configures KCSAN to follow the Linux-kernel memory consistency model (LKMM) as +closely as possible. + DebugFS interface ~~~~~~~~~~~~~~~~~ diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan index 5304f21..c76fbb3 100644 --- a/lib/Kconfig.kcsan +++ b/lib/Kconfig.kcsan @@ -183,9 +183,17 @@ config KCSAN_REPORT_RACE_UNKNOWN_ORIGIN reported if it was only possible to infer a race due to a data value change while an access is being delayed on a watchpoint. +config KCSAN_STRICT + bool "Strict data-race checking" + help + KCSAN will report data races with the strictest possible rules, which + closely aligns with the rules defined by the Linux-kernel memory + consistency model (LKMM). + config KCSAN_REPORT_VALUE_CHANGE_ONLY bool "Only report races where watcher observed a data value change" default y + depends on !KCSAN_STRICT help If enabled and a conflicting write is observed via a watchpoint, but the data value of the memory location was observed to remain @@ -194,6 +202,7 @@ config KCSAN_REPORT_VALUE_CHANGE_ONLY config KCSAN_ASSUME_PLAIN_WRITES_ATOMIC bool "Assume that plain aligned writes up to word size are atomic" default y + depends on !KCSAN_STRICT help Assume that plain aligned writes up to word size are atomic by default, and also not subject to other unsafe compiler optimizations @@ -206,6 +215,7 @@ config KCSAN_ASSUME_PLAIN_WRITES_ATOMIC config KCSAN_IGNORE_ATOMICS bool "Do not instrument marked atomic accesses" + depends on !KCSAN_STRICT help Never instrument marked atomic accesses. This option can be used for additional filtering. Conflicting marked atomic reads and plain
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