From: Shan Hai <haishan.bai@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org, eric.dumazet@gmail.com,
vapier@gentoo.org, asharma@fb.com, linux-kernel@vger.kernel.org,
linux-rt-users@vger.kernel.org
Subject: Re: [PATCH V2 1/1] lib/atomic64 using raw_spin_lock_irq[save|resotre] for atomicity
Date: Fri, 02 Sep 2011 08:48:33 +0800 [thread overview]
Message-ID: <4E6027E1.1090905@gmail.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1109011209000.2723@ionos>
On 09/01/2011 06:11 PM, Thomas Gleixner wrote:
> On Thu, 1 Sep 2011, Thomas Gleixner wrote:
>
>> On Thu, 1 Sep 2011, Shan Hai wrote:
>>
>>> The spin_lock_irq[save|restore] could break the atomicity of the
>>> atomic64_* operations in the PREEMPT-RT configuration, because
>>> the spin_lock_irq[save|restore] themselves are preemptable in the
>>> PREEMPT-RT, using raw variant of the spin lock could provide the
>>> atomicity that atomic64_* need.
>> Good catch. Queued for the next release.
> Though the changelog is misleading. The reason is not that they are
> preemtible.
>
> The reason for your OOPs is that the sleeping locks are not IRQ
> safe. And your system simply deadlocked due to that.
>
Will correct it in the V3 patch, thanks for the advice.
Cheers
Shan Hai
> Thanks,
>
> tglx
> --
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prev parent reply other threads:[~2011-09-02 0:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-01 3:32 [PATCH V2 0/1] lib/atomic64 using raw_spin_lock_irq[save|resotre] for atomicity Shan Hai
2011-09-01 3:32 ` [PATCH V2 1/1] " Shan Hai
2011-09-01 5:27 ` Yong Zhang
2011-09-01 9:59 ` Thomas Gleixner
2011-09-01 10:11 ` Thomas Gleixner
2011-09-02 0:48 ` Shan Hai [this message]
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