On Thu, Feb 13, 2014 at 04:14:36PM -0800, Greg KH wrote: > On Fri, Feb 14, 2014 at 12:07:17AM +0000, Russell King - ARM Linux wrote: > > On Thu, Feb 13, 2014 at 03:26:06PM -0800, Greg KH wrote: > > > On Thu, Feb 13, 2014 at 06:42:49PM +0000, Russell King - ARM Linux wrote: > > > > We went through this before, and I stated the paths, and no one disagreed > > > > with that. > > > > > > > > It /is/ racy. > > > > > > Ok, I just went and looked at the uart driver register path, and I don't > > > see the race (note, if there is one, it's there today, regardless of > > > this patch). > > > > The race isn't the uart code, it's the driver model. > > > > Consider what happens when this happens: > > > > * Two pl011 devices get registered at the same time by two different > > threads. > > How? What two different busses will see this same device? The amba bus > code should prevent that from happening, right? If not, there's bigger > problems in that bus code :) Where is that requirement documented? It isn't documented. No one implements any kind of locking at the bus level to prevent this, not PCI, nor platform devices. > That's where this problem should be fixed, if there is one, otherwise > this same issue would be there for any type of driver that calles into > the uart core, right? And how does bus code prevent this? By intercepting the driver model ->probe callback and taking its own lock maybe? Really? What about those buses which don't wrap the probe callback? -- FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. Estimate before purchase was "up to 13.2Mbit". -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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