From: Thomas Gleixner <tglx@linutronix.de>
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, mpe@ellerman.id.au, paulmck@kernel.org,
paulus@samba.org, peterz@infradead.org, rth@twiddle.net,
shorne@gmail.com, stefan.kristiansson@saunalahti.fi,
vincent.guittot@linaro.org, will@kernel.org
Subject: Re: [RFC PATCH 01/10] thread_info: add helpers to snapshot thread flags
Date: Sun, 20 Jun 2021 00:28:04 +0200 [thread overview]
Message-ID: <87h7hth4ln.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20210609122001.18277-2-mark.rutland@arm.com>
On Wed, Jun 09 2021 at 13:19, Mark Rutland wrote:
> We have common helpers to manipulate individual thread flags, but where
> code wants to check several flags at once, it must open code reading
> current_thread_info()->flags and operating on a snapshot.
Who's we?
> As some flags can be set remotely it's necessary to use READ_ONCE() to
> get a consistent snapshot even when IRQs are disabled, but some code
> forgets to do this. Generally this is unlike to cause a problem in
> practice, but it is somewhat unsound, and KCSAN will legitimately warn
> that there is a data race.
>
> To make it easier to do the right thing, and to highlight that
> concurrent modification is possible, let's add a new helpers to
> snapshot
let's add? Why not simply "add"?
> +static inline unsigned long read_ti_thread_flags(struct thread_info *ti)
__always_inline() as Marco pointed out already
Other than those nitpicks:
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
next prev parent reply other threads:[~2021-06-19 22:28 UTC|newest]
Thread overview: 21+ 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 [this message]
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
2021-06-16 22:07 ` kernel test robot
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
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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