genirq: Run irq handlers with interrupts disabled
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From: Thomas Gleixner on 2 Apr 2010 16:50 On Fri, 2 Apr 2010, Pavel Machek wrote: > On Wed 2010-03-31 13:16:37, Thomas Gleixner wrote: > > On Tue, 30 Mar 2010, Andi Kleen wrote: > > > > > > Why not simply force IRQF_DISABLED for all MSI interrupts. That still > > > > allows nesting for non MSI ones, but it limits the chance of throwing > > > > up reasonably well. That's a two liner. > > > > > > > > Can you please test whether it resolves the issue at hand ? > > > > > > Sorry for the late answer. Got confirmation that this patch > > > fixes the test case. Thanks. > > > > Ok, I'll push it linus wards and cc stable. I think thats the least > > intrusive safe bet we can have right now. > > stable? I'd say thats way too intrusive for -stable... So we better let the possible stack overruns unaddressed ? Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Pavel Machek on 2 Apr 2010 17:10 On Fri 2010-04-02 22:42:51, Thomas Gleixner wrote: > On Fri, 2 Apr 2010, Pavel Machek wrote: > > > On Wed 2010-03-31 13:16:37, Thomas Gleixner wrote: > > > On Tue, 30 Mar 2010, Andi Kleen wrote: > > > > > > > > Why not simply force IRQF_DISABLED for all MSI interrupts. That still > > > > > allows nesting for non MSI ones, but it limits the chance of throwing > > > > > up reasonably well. That's a two liner. > > > > > > > > > > Can you please test whether it resolves the issue at hand ? > > > > > > > > Sorry for the late answer. Got confirmation that this patch > > > > fixes the test case. Thanks. > > > > > > Ok, I'll push it linus wards and cc stable. I think thats the least > > > intrusive safe bet we can have right now. > > > > stable? I'd say thats way too intrusive for -stable... > > So we better let the possible stack overruns unaddressed ? -stable should have no regressions, first and foremost. And this is pretty certain to introduce some, at least on low-powered system with serial ports. So yes, it is probably better to let the possible stack overruns unaddressed. We have lived with them for 15 years or so... (Alternatively, just make the irq stacks bigger? Or just take Andi's patch, which solves the overruns, and only introduces latency regressions when it would otherwise crash?) Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Peter Zijlstra on 2 Apr 2010 17:40 On Fri, 2010-04-02 at 23:09 +0200, Pavel Machek wrote: > On Fri 2010-04-02 22:42:51, Thomas Gleixner wrote: > > On Fri, 2 Apr 2010, Pavel Machek wrote: > > > > > On Wed 2010-03-31 13:16:37, Thomas Gleixner wrote: > > > > On Tue, 30 Mar 2010, Andi Kleen wrote: > > > > > > > > > > Why not simply force IRQF_DISABLED for all MSI interrupts. That still > > > > > > allows nesting for non MSI ones, but it limits the chance of throwing > > > > > > up reasonably well. That's a two liner. > > > > > > > > > > > > Can you please test whether it resolves the issue at hand ? > > > > > > > > > > Sorry for the late answer. Got confirmation that this patch > > > > > fixes the test case. Thanks. > > > > > > > > Ok, I'll push it linus wards and cc stable. I think thats the least > > > > intrusive safe bet we can have right now. > > > > > > stable? I'd say thats way too intrusive for -stable... > > > > So we better let the possible stack overruns unaddressed ? > > -stable should have no regressions, first and foremost. And this is > pretty certain to introduce some, at least on low-powered system with > serial ports. > > So yes, it is probably better to let the possible stack overruns > unaddressed. We have lived with them for 15 years or so... > > (Alternatively, just make the irq stacks bigger? Or just take Andi's > patch, which solves the overruns, and only introduces latency > regressions when it would otherwise crash?) You've got serial ports with MSI interrupts? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Thomas Gleixner on 2 Apr 2010 19:00 Pavel, On Fri, 2 Apr 2010, Pavel Machek wrote: > On Fri 2010-04-02 22:42:51, Thomas Gleixner wrote: > > On Fri, 2 Apr 2010, Pavel Machek wrote: > > > > > On Wed 2010-03-31 13:16:37, Thomas Gleixner wrote: > > > > On Tue, 30 Mar 2010, Andi Kleen wrote: > > > > > > > > > > Why not simply force IRQF_DISABLED for all MSI interrupts. That still > > > > > > allows nesting for non MSI ones, but it limits the chance of throwing > > > > > > up reasonably well. That's a two liner. > > > > > > > > > > > > Can you please test whether it resolves the issue at hand ? > > > > > > > > > > Sorry for the late answer. Got confirmation that this patch > > > > > fixes the test case. Thanks. > > > > > > > > Ok, I'll push it linus wards and cc stable. I think thats the least > > > > intrusive safe bet we can have right now. > > > > > > stable? I'd say thats way too intrusive for -stable... > > > > So we better let the possible stack overruns unaddressed ? > > -stable should have no regressions, first and foremost. And this is > pretty certain to introduce some, at least on low-powered system with > serial ports. I think you misunderstood what I'm going to push. The patch merily forces IRQF_DISABLED for MSI(X) based interrupts. So that does not affect low powered systems in any way. It only affects high end systems where Dave Miller already said he did the IRQF_DISABLED magic already in some NIC drivers just to prevent that. So I think your fear of regressions for low-powered systems is completely unsubstantiated. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Pavel Machek on 3 Apr 2010 00:50
On Sat 2010-04-03 00:51:20, Thomas Gleixner wrote: > Pavel, > > On Fri, 2 Apr 2010, Pavel Machek wrote: > > > On Fri 2010-04-02 22:42:51, Thomas Gleixner wrote: > > > On Fri, 2 Apr 2010, Pavel Machek wrote: > > > > > > > On Wed 2010-03-31 13:16:37, Thomas Gleixner wrote: > > > > > On Tue, 30 Mar 2010, Andi Kleen wrote: > > > > > > > > > > > > Why not simply force IRQF_DISABLED for all MSI interrupts. That still > > > > > > > allows nesting for non MSI ones, but it limits the chance of throwing > > > > > > > up reasonably well. That's a two liner. > > > > > > > > > > > > > > Can you please test whether it resolves the issue at hand ? > > > > > > > > > > > > Sorry for the late answer. Got confirmation that this patch > > > > > > fixes the test case. Thanks. > > > > > > > > > > Ok, I'll push it linus wards and cc stable. I think thats the least > > > > > intrusive safe bet we can have right now. > > > > > > > > stable? I'd say thats way too intrusive for -stable... > > > > > > So we better let the possible stack overruns unaddressed ? > > > > -stable should have no regressions, first and foremost. And this is > > pretty certain to introduce some, at least on low-powered system with > > serial ports. > > I think you misunderstood what I'm going to push. The patch merily > forces IRQF_DISABLED for MSI(X) based interrupts. So that does not > affect low powered systems in any way. > > It only affects high end systems where Dave Miller already said he did > the IRQF_DISABLED magic already in some NIC drivers just to prevent > that. Oops, yes, I did; lost in all the mails. > So I think your fear of regressions for low-powered systems is > completely unsubstantiated. Yep. Sorry for the noise. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |