Commit e675d253 authored by Marco Elver's avatar Marco Elver Committed by Paul E. McKenney
Browse files

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: default avatarMarco Elver <elver@google.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent a7a73697

Documentation/dev-tools/kcsan.rst

+4 −0
Original line number Diff line number Diff line
@@ -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

~~~~~~~~~~~~~~~~~

lib/Kconfig.kcsan

+10 −0
Original line number Diff line number Diff line
@@ -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