Subject: Re: [PATCH] x86/ioapic: Fix the vector_irq[] is corrupted randomly
From: Suresh Siddha <suresh.b.siddha@intel.com>
Reply-To: Suresh Siddha <suresh.b.siddha@intel.com>
To: Chuansheng Liu <chuansheng.liu@intel.com>
Cc: mingo@redhat.com, hpa@zytor.com, tglx@linutronix.de, yinghai@kernel.org,
        x86@kernel.org, linux-kernel@vger.kernel.org
Date: Mon, 29 Oct 2012 13:24:04 -0700
In-Reply-To: <1351527341.15558.1445.camel@cliu38-desktop-build>
References: <1351527341.15558.1445.camel@cliu38-desktop-build>
Organization: Intel Corp
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Message-ID: <1351542245.12459.39.camel@sbsiddha-desk.sc.intel.com>
Mime-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1759
Lines: 43

On Tue, 2012-10-30 at 00:15 +0800, Chuansheng Liu wrote:
> Not all irq chips are IO-APIC chip.
> 
> In our system, there are many demux GPIO interrupts except for the
> io-apic chip interrupts, and these GPIO interrupts are belonged
> to other irq chips, the chip data is not type of struct irq_cfg
> either.
> 
> But in function __setup_vector_irq(), it listed all allocated irqs,
> and presume all irq chip is ioapic_chip and the chip data is type
> of struct irq_cfg, it possibly causes the vector_irq is corrupted
> randomly.
> 
> For example, one irq 258 is not io-apic chip irq, in __setup_vector_irq(),
> the chip data is forced to be used as struct irq_cfg, then the value
> cfg->domain and cfg->vector are wrong to be used to write vector_irq:
> 		vector = cfg->vector;
> 		per_cpu(vector_irq, cpu)[vector] = irq;
> 
> This patch use the .flags to identify if the irq chip is io-apic.

I have a feeling that your gpio driver is abusing the 'chip_data' in the
struct irq_data. Shouldn't the driver be using 'handler_data' instead?

>From include/linux/irq.h:
 * @handler_data:       per-IRQ data for the irq_chip methods
 * @chip_data:          platform-specific per-chip private data for the chip
 *                      methods, to allow shared chip implementations

Also, how are these routed to the processors and the mechanism of the
vector assignment for these irq's? I presume irq_cfg is needed for the
setup and the interrupt migration from one cpu to another.

What am I missing?

thanks,
suresh

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/