From: Marco Elver <elver@google.com>
To: elver@google.com
Cc: paulmck@kernel.org, andreyknvl@google.com, glider@google.com,
dvyukov@google.com, kasan-dev@googlegroups.com,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/3] kcsan: Clarify Kconfig option KCSAN_IGNORE_ATOMICS
Date: Tue, 4 Feb 2020 18:21:11 +0100 [thread overview]
Message-ID: <20200204172112.234455-2-elver@google.com> (raw)
In-Reply-To: <20200204172112.234455-1-elver@google.com>
Clarify difference between options KCSAN_IGNORE_ATOMICS and
KCSAN_ASSUME_PLAIN_WRITES_ATOMIC in help text.
Signed-off-by: Marco Elver <elver@google.com>
---
v2:
* Update help text to mention alignment w.r.t. previous option.
---
lib/Kconfig.kcsan | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index 66126853dab02..020ac63e43617 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
--
2.25.0.341.g760bfbb309-goog
next prev parent reply other threads:[~2020-02-04 17:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-04 17:21 [PATCH v2 1/3] kcsan: Add option to assume plain aligned writes up to word size are atomic Marco Elver
2020-02-04 17:21 ` Marco Elver [this message]
2020-02-04 17:21 ` [PATCH v2 3/3] kcsan: Cleanup of main KCSAN Kconfig option Marco Elver
2020-02-04 18:16 ` [PATCH v2 1/3] kcsan: Add option to assume plain aligned writes up to word size are atomic Paul E. McKenney
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