The following commit has been merged into the locking/kcsan branch of tip: Commit-ID: a249a73231e2e30944b948c5351025e5ff65f6d1 Gitweb: https://git.kernel.org/tip/a249a73231e2e30944b948c5351025e5ff65f6d1 Author: Marco Elver <elver@xxxxxxxxxx> AuthorDate: Tue, 04 Feb 2020 18:21:11 +01:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Sat, 21 Mar 2020 09:42:21 +01:00 kcsan: Clarify Kconfig option KCSAN_IGNORE_ATOMICS Clarify difference between options KCSAN_IGNORE_ATOMICS and KCSAN_ASSUME_PLAIN_WRITES_ATOMIC in help text. Signed-off-by: Marco Elver <elver@xxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- lib/Kconfig.kcsan | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan index 6612685..020ac63 100644 --- a/lib/Kconfig.kcsan +++ b/lib/Kconfig.kcsan @@ -132,8 +132,18 @@ config KCSAN_ASSUME_PLAIN_WRITES_ATOMIC config KCSAN_IGNORE_ATOMICS bool "Do not instrument marked atomic accesses" help - If enabled, never instruments marked atomic accesses. This results in - not reporting data races where one access is atomic and the other is - a plain access. + Never instrument marked atomic accesses. This option can be used for + additional filtering. Conflicting marked atomic reads and plain + writes will never be reported as a data race, however, will cause + plain reads and marked writes to result in "unknown origin" reports. + If combined with CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN=n, data + races where at least one access is marked atomic will never be + reported. + + Similar to KCSAN_ASSUME_PLAIN_WRITES_ATOMIC, but including unaligned + accesses, conflicting marked atomic reads and plain writes will not + be reported as data races; however, unlike that option, data races + due to two conflicting plain writes will be reported (aligned and + unaligned, if CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC=n). endif # KCSAN
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