linux-kernel - Re: [PATCH 0/7] kcsan: Introduce CONFIG_KCSAN

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Date:   Tue, 15 Jun 2021 20:51:18 +0200
From:   Marco Elver <elver@...gle.com>
To:     "Paul E. McKenney" <paulmck@...nel.org>
Cc:     Mark Rutland <mark.rutland@....com>, boqun.feng@...il.com,
        will@...nel.org, glider@...gle.com, dvyukov@...gle.com,
        kasan-dev@...glegroups.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/7] kcsan: Introduce CONFIG_KCSAN_PERMISSIVE

On Tue, Jun 15, 2021 at 11:19AM -0700, Paul E. McKenney wrote:
[...]
> Queued and pushed for v5.15, thank you both!
> 
> I also queued the following patch making use of CONFIG_KCSAN_STRICT, and I
> figured that I should run it past you guys to make check my understanding.
> 
> Thoughts?

You still need CONFIG_KCSAN_INTERRUPT_WATCHER=y, but otherwise looks
good.

I thought I'd leave that out for now, but now thinking about it, we
might as well imply interruptible watchers. If you agree, feel free to
queue the below patch ahead of yours.

Thanks,
-- Marco

------ >8 ------

From: Marco Elver <elver@...gle.com>
Date: Tue, 15 Jun 2021 20:39:38 +0200
Subject: [PATCH] kcsan: Make strict mode imply interruptible watchers

If CONFIG_KCSAN_STRICT=y, select CONFIG_KCSAN_INTERRUPT_WATCHER as well.

With interruptible watchers, we'll also report same-CPU data races; if
we requested strict mode, we might as well show these, too.

Suggested-by: Paul E. McKenney <paulmck@...nel.org>
Signed-off-by: Marco Elver <elver@...gle.com>
---
 lib/Kconfig.kcsan | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index 26f03c754d39..e0a93ffdef30 100644
--- a/lib/Kconfig.kcsan
+++ b/lib/Kconfig.kcsan
@@ -150,7 +150,8 @@ config KCSAN_SKIP_WATCH_RANDOMIZE
 	  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
-- 
2.32.0.272.g935e593368-goog