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From:   Qian Cai <cai@lca.pw>
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Subject: Re: [PATCH v4 01/10] kcsan: Add Kernel Concurrency Sanitizer infrastructure
Date:   Tue, 14 Jan 2020 15:30:53 -0500
Message-Id: <F185919B-2D86-43B6-9BEC-D14D72871A58@lca.pw>
References: <20200114192220.GS2935@paulmck-ThinkPad-P72>
Cc:     Marco Elver <elver@google.com>,
        LKMM Maintainers -- Akira Yokosawa <akiyks@gmail.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        Alexander Potapenko <glider@google.com>,
        Andrea Parri <parri.andrea@gmail.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Boqun Feng <boqun.feng@gmail.com>,
        Borislav Petkov <bp@alien8.de>, Daniel Axtens <dja@axtens.net>,
        Daniel Lustig <dlustig@nvidia.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        David Howells <dhowells@redhat.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Jade Alglave <j.alglave@ucl.ac.uk>,
        Joel Fernandes <joel@joelfernandes.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Luc Maranget <luc.maranget@inria.fr>,
        Mark Rutland <Mark.Rutland@arm.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <will@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        linux-arch <linux-arch@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        linux-efi@vger.kernel.org,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        the arch/x86 maintainers <x86@kernel.org>
In-Reply-To: <20200114192220.GS2935@paulmck-ThinkPad-P72>
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> On Jan 14, 2020, at 2:22 PM, Paul E. McKenney <paulmck@kernel.org> wrote:
>=20
> Just so I understand...  Does this problem happen even in CONFIG_KCSAN=3Dn=

> kernels?

No.

>=20
> I have been running extensive CONFIG_KSCAN=3Dy rcutorture tests for quite
> awhile now, so even if this only happens for CONFIG_KSCAN=3Dy, it is not
> like it affects everyone.
>=20
> Yes, it should be fixed, and Marco does have a patch on the way.

The concern is really about setting KSCAN=3Dy in a distro debug kernel where=
 it has other debug options. I=E2=80=99ll try to dig into more of those issu=
es in the next few days.=