linux-kernel - [tip: locking/kcsan] kcsan: Clarify Kconfig option KCSAN_IGNORE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <158504105829.28353.13995420302647105677.tip-bot2@tip-bot2>
Date:   Tue, 24 Mar 2020 09:10:58 -0000
From:   "tip-bot2 for Marco Elver" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Marco Elver <elver@...gle.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Ingo Molnar <mingo@...nel.org>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: locking/kcsan] kcsan: Clarify Kconfig option KCSAN_IGNORE_ATOMICS

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@...gle.com>
AuthorDate:    Tue, 04 Feb 2020 18:21:11 +01:00
Committer:     Ingo Molnar <mingo@...nel.org>
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@...gle.com>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 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