From: Marco Elver <elver@google.com>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>,
rust-for-linux@vger.kernel.org
Subject: Re: Can the Kernel Concurrency Sanitizer Own Rust Code?
Date: Thu, 7 Oct 2021 16:22:41 +0200 [thread overview]
Message-ID: <CANpmjNOA3NfGDLK2dribst+0899GrwWsinMp7YKYiGvAjnT-qA@mail.gmail.com> (raw)
In-Reply-To: <YV8A5iQczHApZlD6@boqun-archlinux>
On Thu, 7 Oct 2021 at 16:16, Boqun Feng <boqun.feng@gmail.com> wrote:
[...]
> > Also of importance will be the __tsan_atomic*() instrumentation, which
> > KCSAN already provides: my guess is that whatever subset of the LKMM
> > Rust initially provides (looking at the current version it certainly
> > is the case), the backend will lower them to LLVM atomic intrinsics
> > [1], which ThreadSanitizer instrumentation turns into __tsan_atomic*()
> > calls.
> > [1] https://llvm.org/docs/Atomics.html
> >
>
> Besides atomics, the counterpart of READ_ONCE() and WRITE_ONCE() should
> also be looked into, IOW the core::ptr::{read,write}_volatile()
> (although I don't think their semantics is completely defined since the
> memory model of Rust is incomplete). There could easily be cases where
> Rust-side do writes with lock critical sections while C-side do reads
> out of the lock critical sections, so Rust-side need to play the
> volatile game.
>
> I'm not sure whether rustc will generate special instrumentation for
> {read,write}_volatile(), if not, we need to provide something similar to
> KCSAN does for READ_ONCE() and WRITE_ONCE().
For volatile (i.e. *ONCE()) KCSAN no longer does anything special.
This was one of the major compiler changes (-mllvm
-tsan-distinguish-volatile=1, and similarly for GCC) to get KCSAN
merged in the end.
So if rustc lowers core::ptr::{read,write}_volatile() to volatile in
LLVM IR (which I assume it does), then everything works as intended,
and no extra explicit instrumentation is required.
Thanks,
-- Marco
next prev parent reply other threads:[~2021-10-07 14:22 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-07 13:01 Can the Kernel Concurrency Sanitizer Own Rust Code? Marco Elver
2021-10-07 14:15 ` Boqun Feng
2021-10-07 14:22 ` Marco Elver [this message]
2021-10-07 14:43 ` Boqun Feng
2021-10-07 17:44 ` Miguel Ojeda
2021-10-07 18:50 ` Paul E. McKenney
2021-10-07 21:42 ` Gary Guo
2021-10-07 22:30 ` Paul E. McKenney
2021-10-07 23:06 ` Gary Guo
2021-10-07 23:42 ` Paul E. McKenney
2021-10-07 23:59 ` Gary Guo
2021-10-08 0:27 ` comex
2021-10-08 17:40 ` Paul E. McKenney
2021-10-08 21:32 ` Miguel Ojeda
2021-10-09 0:08 ` Paul E. McKenney
2021-10-09 16:31 ` Miguel Ojeda
2021-10-09 23:59 ` Paul E. McKenney
2021-10-11 1:24 ` Miguel Ojeda
2021-10-11 19:01 ` Paul E. McKenney
2021-10-13 11:48 ` Miguel Ojeda
2021-10-13 16:07 ` Paul E. McKenney
2021-10-13 17:50 ` Wedson Almeida Filho
2021-10-14 3:35 ` Paul E. McKenney
2021-10-14 8:03 ` Wedson Almeida Filho
2021-10-14 19:43 ` Paul E. McKenney
2021-10-15 15:06 ` Wedson Almeida Filho
2021-10-15 23:29 ` Paul E. McKenney
2021-10-08 19:53 ` Miguel Ojeda
2021-10-08 23:57 ` Paul E. McKenney
2021-10-09 16:30 ` Miguel Ojeda
2021-10-09 23:48 ` Paul E. McKenney
2021-10-11 0:59 ` Miguel Ojeda
2021-10-11 18:52 ` Paul E. McKenney
2021-10-13 11:47 ` Miguel Ojeda
2021-10-13 23:29 ` Paul E. McKenney
2021-10-22 19:17 ` Miguel Ojeda
2021-10-22 20:34 ` Paul E. McKenney
2021-10-07 16:30 ` Paul E. McKenney
2021-10-07 16:35 ` Marco Elver
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