if KCSAN
-# Compiler capabilities that should not fail the test if they are unavailable.
config CC_HAS_TSAN_COMPOUND_READ_BEFORE_WRITE
def_bool (CC_IS_CLANG && $(cc-option,-fsanitize=thread -mllvm -tsan-compound-read-before-write=1)) || \
(CC_IS_GCC && $(cc-option,-fsanitize=thread --param tsan-compound-read-before-write=1))
+ help
+ The compiler instruments plain compound read-write operations
+ differently (++, --, +=, -=, |=, &=, etc.), which allows KCSAN to
+ distinguish them from other plain accesses. This is currently
+ supported by Clang 12 or later.
config KCSAN_VERBOSE
bool "Show verbose reports with more information about system state"
generated from any one of them, system stability may suffer due to
deadlocks or recursion. If in doubt, say N.
-config KCSAN_DEBUG
- bool "Debugging of KCSAN internals"
-
config KCSAN_SELFTEST
bool "Perform short selftests on boot"
default y
KCSAN_WATCH_SKIP.
config KCSAN_INTERRUPT_WATCHER
- bool "Interruptible watchers"
+ bool "Interruptible watchers" if !KCSAN_STRICT
+ default KCSAN_STRICT
help
If enabled, a task that set up a watchpoint may be interrupted while
delayed. This option will allow KCSAN to detect races between
reporting to avoid flooding the console with reports. Setting this
to 0 disables rate limiting.
-# The main purpose of the below options is to control reported data races (e.g.
-# in fuzzer configs), and are not expected to be switched frequently by other
-# users. We could turn some of them into boot parameters, but given they should
-# not be switched normally, let's keep them here to simplify configuration.
-#
-# The defaults below are chosen to be very conservative, and may miss certain
-# bugs.
+# The main purpose of the below options is to control reported data races, and
+# are not expected to be switched frequently by non-testers or at runtime.
+# The defaults are chosen to be conservative, and can miss certain bugs.
config KCSAN_REPORT_RACE_UNKNOWN_ORIGIN
bool "Report races of 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
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
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
due to two conflicting plain writes will be reported (aligned and
unaligned, if CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC=n).
+config KCSAN_PERMISSIVE
+ bool "Enable all additional permissive rules"
+ depends on KCSAN_REPORT_VALUE_CHANGE_ONLY
+ help
+ Enable additional permissive rules to ignore certain classes of data
+ races (also see kernel/kcsan/permissive.h). None of the permissive
+ rules imply that such data races are generally safe, but can be used
+ to further reduce reported data races due to data-racy patterns
+ common across the kernel.
+
endif # KCSAN