From: Eugeniu Rosca <erosca@de.adit-jv.com>
To: Balasubramani Vivekanandan <balasubramani_vivekanandan@mentor.com>
Cc: <fweisbec@gmail.com>, <tglx@linutronix.de>, <mingo@kernel.org>,
<peterz@infradead.org>, <linux-renesas-soc@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Eugeniu Rosca <erosca@de.adit-jv.com>,
Eugeniu Rosca <roscaeugeniu@gmail.com>
Subject: Re: [PATCH V3 1/1] tick: broadcast-hrtimer: Fix a race in bc_set_next
Date: Thu, 26 Sep 2019 17:43:56 +0200 [thread overview]
Message-ID: <20190926154356.GA29221@vmlxhi-102.adit-jv.com> (raw)
In-Reply-To: <20190926135101.12102-2-balasubramani_vivekanandan@mentor.com>
On Thu, Sep 26, 2019 at 03:51:01PM +0200, Balasubramani Vivekanandan wrote:
> When a cpu requests broadcasting, before starting the tick broadcast
> hrtimer, bc_set_next() checks if the timer callback (bc_handler) is
> active using hrtimer_try_to_cancel(). But hrtimer_try_to_cancel() does
> not provide the required synchronization when the callback is active on
> other core.
[..]
> diff --git a/kernel/time/tick-broadcast-hrtimer.c b/kernel/time/tick-broadcast-hrtimer.c
> index c1f5bb590b5e..f070f9734792 100644
> --- a/kernel/time/tick-broadcast-hrtimer.c
> +++ b/kernel/time/tick-broadcast-hrtimer.c
[..]
FWIW, the patch seems to fix the very first commit adding hrtimer
broadcast, i.e. v3.15-rc1 commit 5d1638acb9f62f ("tick: Introduce
hrtimer based broadcast"), so maybe adding a Fixes: tag could be
relevant/beneficial for the stable trees?
--
Best Regards,
Eugeniu
prev parent reply other threads:[~2019-09-26 15:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190918144138.24839-1-balasubramani_vivekanandan@mentor.com>
2019-09-20 10:58 ` [PATCH V1 0/1] tick: broadcast-hrtimer: Fix a race in bc_set_next Eugeniu Rosca
[not found] ` <20190918144138.24839-2-balasubramani_vivekanandan@mentor.com>
[not found] ` <alpine.DEB.2.21.1909232041080.1934@nanos.tec.linutronix.de>
2019-09-24 17:14 ` [PATCH V1 1/1] " Eugeniu Rosca
[not found] ` <20190925115541.1170-1-balasubramani_vivekanandan@mentor.com>
2019-09-25 13:32 ` [PATCH V2 " Balasubramani Vivekanandan
2019-09-25 14:20 ` Balasubramani Vivekanandan
2019-09-25 14:20 ` Balasubramani Vivekanandan
2019-09-26 10:01 ` Thomas Gleixner
2019-09-26 13:51 ` [PATCH V3 " Balasubramani Vivekanandan
2019-09-26 13:51 ` Balasubramani Vivekanandan
2019-09-26 15:43 ` Eugeniu Rosca [this message]
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