From: Wang YanQing <udknight@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Chuansheng Liu <chuansheng.liu@intel.com>,
mingo@kernel.org, peterz@infradead.org, jbeulich@suse.com,
paulmck@linux.vnet.ibm.com, akpm@linux-foundation.org,
mina86@mina86.org, srivatsa.bhat@linux.vnet.ibm.com,
linux-kernel@vger.kernel.org, jun.zhang@intel.com,
fengguang.wu@intel.com
Subject: Re: [PATCH V2] smp: Give WARN()ing when calling smp_call_function_many()/single() in serving irq
Date: Sun, 7 Jul 2013 11:59:07 +0800 [thread overview]
Message-ID: <20130707035907.GA2875@udknight> (raw)
In-Reply-To: <alpine.DEB.2.02.1307051615100.32106@ionos.tec.linutronix.de>
On Fri, Jul 05, 2013 at 04:37:14PM +0200, Thomas Gleixner wrote:
> Hmm, even there it matters, because of the following scenario:
>
> CPU 0
> smp_call_function_single(CPU 1)
> csd_lock(CPU 1)
No, smpl_call_function_single(CPU 1)
will csd_lock(CPU 0), not csd_lock(CPU 1)
> irq_enter()
> irq_exit()
> __do_softirq()
> smp_call_function_many()
> setup csd (CPU 1)
> csd_lock(CPU 1) ==> CPU 0 deadlocked itself.
>
maybe below is the scenario:
irq_enter()
irq_exit()
__do_softirq()
smp_call_function_single()
setup csd (CPU 1)
csd_lock(CPU 0) ==> CPU 0 deadlocked itself.
> And this is even more likely to happen than the lock issue.
>
> Thanks,
>
> tglx
> --
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next prev parent reply other threads:[~2013-07-07 3:59 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-06 15:18 [PATCH] smp: give WARN in case of in_interrupt() when calling smp_call_function_many/single Chuansheng Liu
2013-02-06 13:42 ` [tip:core/locking] smp: Give WARN()ing if in_interrupt() when calling smp_call_function_many()/single() tip-bot for Chuansheng Liu
2013-02-11 12:20 ` [tip:core/locking] Revert "smp: Give WARN()ing if in_interrupt() when calling smp_call_function_many()/single()" tip-bot for Ingo Molnar
2013-02-16 5:26 ` Liu, Chuansheng
2013-02-16 13:57 ` [PATCH] smp: Give WARN()ing when calling smp_call_function_many()/single() in serving irq Chuansheng Liu
2013-02-16 14:10 ` [PATCH V2] " Chuansheng Liu
2013-02-18 1:38 ` Fengguang Wu
2013-02-19 23:01 ` Andrew Morton
2013-02-20 1:06 ` Fengguang Wu
2013-02-20 1:22 ` Liu, Chuansheng
2013-02-27 14:50 ` Lai Jiangshan
2013-03-01 3:37 ` Liu, Chuansheng
2013-08-05 22:46 ` Andrew Morton
2013-07-05 13:50 ` Thomas Gleixner
2013-07-05 14:37 ` Thomas Gleixner
2013-07-07 3:59 ` Wang YanQing [this message]
2013-07-07 13:47 ` Thomas Gleixner
2013-12-06 1:29 ` Max Filippov
2013-12-06 14:02 ` Thomas Gleixner
2013-12-06 18:31 ` Max Filippov
2013-07-07 2:41 ` Wang YanQing
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