From: Michael Ellerman <mpe@ellerman.id.au>
To: Mark Rutland <mark.rutland@arm.com>, linux-kernel@vger.kernel.org
Cc: benh@kernel.crashing.org, boqun.feng@gmail.com, bp@alien8.de,
catalin.marinas@arm.com, dvyukov@google.com, elver@google.com,
ink@jurassic.park.msu.ru, jonas@southpole.se,
juri.lelli@redhat.com, linux@armlinux.org.uk, luto@kernel.org,
mark.rutland@arm.com, mattst88@gmail.com, mingo@redhat.com,
monstr@monstr.eu, paulmck@kernel.org, paulus@samba.org,
peterz@infradead.org, rth@twiddle.net, shorne@gmail.com,
stefan.kristiansson@saunalahti.fi, tglx@linutronix.de,
vincent.guittot@linaro.org, will@kernel.org
Subject: Re: [RFC PATCH 09/10] powerpc: snapshot thread flags
Date: Tue, 15 Jun 2021 23:18:52 +1000 [thread overview]
Message-ID: <87k0mvtgeb.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20210609122001.18277-10-mark.rutland@arm.com>
Mark Rutland <mark.rutland@arm.com> writes:
> Some thread flags can be set remotely, and so even when IRQs are
> disabled, the flags can change under our feet. Generally this is
> unlikely to cause a problem in practice, but it is somewhat unsound, and
> KCSAN will legitimately warn that there is a data race.
>
> To avoid such issues, we should snapshot the flags prior to using them.
> Let's use the new helpers to do so on powerpc.
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paul Mackerras <paulus@samba.org>
> ---
> arch/powerpc/kernel/interrupt.c | 16 ++++++++--------
> arch/powerpc/kernel/ptrace/ptrace.c | 3 +--
> 2 files changed, 9 insertions(+), 10 deletions(-)
This looks good.
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
But, it clashes terribly with a series I'm planning to take for v5.14
that reworks our interrupt return code.
https://lore.kernel.org/linuxppc-dev/20210610130921.706938-1-npiggin@gmail.com/T/#t
So if you're also targeting v5.14 then it might be best to drop this
patch from the series, and we can do the conversion later.
cheers
next prev parent reply other threads:[~2021-06-15 13:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 12:19 [RFC PATCH 00/10] thread_info: use helpers to snapshot thread flags Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 01/10] thread_info: add " Mark Rutland
2021-06-10 9:01 ` Marco Elver
2021-06-11 9:17 ` Mark Rutland
2021-06-19 22:28 ` Thomas Gleixner
2021-06-21 8:29 ` Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 02/10] entry: " Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 03/10] sched: " Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 04/10] alpha: " Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 05/10] arm: " Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 06/10] arm64: read " Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 07/10] microblaze: snapshot " Mark Rutland
2021-06-09 12:19 ` [RFC PATCH 08/10] openrisc: " Mark Rutland
2021-06-10 19:14 ` Stafford Horne
2021-06-09 12:20 ` [RFC PATCH 09/10] powerpc: " Mark Rutland
2021-06-15 13:18 ` Michael Ellerman [this message]
2021-06-21 8:46 ` Mark Rutland
2021-06-09 12:20 ` [RFC PATCH 10/10] x86: " Mark Rutland
2021-06-19 22:30 ` Thomas Gleixner
2021-06-21 8:35 ` Mark Rutland
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