From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Felipe Balbi <balbi@ti.com>
Cc: Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
Frank Rowand <frank.rowand@am.sony.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linux ARM Kernel Mailing List
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC/PATCH 3/3] arm: omap: convert omap boot_lock to raw
Date: Thu, 1 Aug 2013 14:37:37 +0100 [thread overview]
Message-ID: <20130801133737.GG21614@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1375359165-8411-4-git-send-email-balbi@ti.com>
On Thu, Aug 01, 2013 at 03:12:45PM +0300, Felipe Balbi wrote:
> From: Frank Rowand <frank.rowand@am.sony.com>
>
> The omap boot_lock is used by the secondary processor startup code. The locking
> task is the idle thread, which has idle->sched_class == &idle_sched_class.
> idle_sched_class->enqueue_task == NULL, so if the idle task blocks on the
> lock, the attempt to wake it when the lock becomes available will fail:
>
> try_to_wake_up()
> ...
> activate_task()
> enqueue_task()
> p->sched_class->enqueue_task(rq, p, flags)
>
> Fix by converting boot_lock to a raw spin lock.
>
> [ balbi@ti.com: taken from RT v3.10.4-rt1 patchset ]
>
> Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
There's a whole bunch of these, OMAP is not the only one. If someone's
going to fix one case, the rest should also be fixed. See:
arch/arm/mach-exynos/platsmp.c
arch/arm/mach-msm/platsmp.c
arch/arm/mach-prima2/platsmp.c
arch/arm/mach-spear/platsmp.c
arch/arm/mach-sti/platsmp.c
arch/arm/mach-ux500/platsmp.c
next prev parent reply other threads:[~2013-08-01 13:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-01 12:12 [RFC/PATCH 0/3] arm: omap: patches from -rt Felipe Balbi
2013-08-01 12:12 ` [RFC/PATCH 1/3] i2c/omap: drop the lock hard irq context Felipe Balbi
2013-08-01 12:12 ` [RFC/PATCH 2/3] serial: omap: fix omap lock crap Felipe Balbi
2013-08-01 12:12 ` [RFC/PATCH 3/3] arm: omap: convert omap boot_lock to raw Felipe Balbi
2013-08-01 13:37 ` Russell King - ARM Linux [this message]
2013-08-01 13:48 ` [RFC/PATCH v2] arm: convert arm " Felipe Balbi
2013-08-01 17:07 ` [RFC/PATCH 0/3] arm: omap: patches from -rt Sourav Poddar
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