Messages in this thread Patch in this message | | | Subject | Re: Ingo's realtime_preempt patch causes kernel oops | From | Yann.LEPROVOST@wavecom ... | Date | Tue, 23 May 2006 18:27:15 +0200 |
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I forgot to say that I let SA_SHIRQ as the IRQ line is shared... It seems to work correctly...
Yann
Steven Rostedt <rostedt@goodmis. org> To Daniel Walker <dwalker@mvista.com> 23/05/2006 18:02 cc Yann.LEPROVOST@wavecom.fr, linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu> Subject Re: Ingo's realtime_preempt patch causes kernel oops
On Tue, 2006-05-23 at 08:33 -0700, Daniel Walker wrote: > On Tue, 2006-05-23 at 10:19 -0400, Steven Rostedt wrote: > > > > > The fault is at 0x40 and looking at profile_tick it calls > > user_mode(regs). user_mode(x) is defined in arm as > > (((regs)->ARM_cpsr & 0xf) == 0) > > > > And ARM_cpsr is uregs[16] So if arm has 4 byte words and regs was NULL, > > it would fault on 16*4 = 64 or 0x40 > > > > It looks like the timer interrupt on this board is having a NULL regs > > passed to it when hard interrupts are threads. Which might mean that > > the timer interrupt is itself a thread. > > Hmm, well usually ARM timer interrupts have the SA_TIMER flag .. In > realtime ARM changes SA_TIMER includes SA_NODELAY .. > > In 2.6.17-rc4 > > arch/arm/mach-at91rm9200/time.c > > static struct irqaction at91rm9200_timer_irq = { > .name = "at91_tick", > .flags = SA_SHIRQ | SA_INTERRUPT, > .handler = at91rm9200_timer_interrupt > }; > > No SA_TIMER, and no SA_NODELAY , so i'd imagine it's is in a thread ..
Yep, I would say it is.
Yann, could you try the following patch to see if it makes it better for you. I added SA_NODELAY so that the timer is run in interrupt context, and removed the shared flag, because I have no idea what might share a timer interrupt, and it might cause other bugs. If something needs to share this interrupt, then we need to do something else.
Since I don't have any arm boards, I cant test it, so this wasn't even compiled.
-- Steve
Index: linux-2.6.16-rt23/arch/arm/mach-at91rm9200/time.c =================================================================== --- linux-2.6.16-rt23.orig/arch/arm/mach-at91rm9200/time.c 2006-05-23 11:58:21.000000000 -0400 +++ linux-2.6.16-rt23/arch/arm/mach-at91rm9200/time.c 2006-05-23 11:58:45.000000000 -0400 @@ -87,7 +87,7 @@ static irqreturn_t at91rm9200_timer_inte
static struct irqaction at91rm9200_timer_irq = { .name = "at91_tick", - .flags = SA_SHIRQ | SA_INTERRUPT, + .flags = SA_INTERRUPT | SA_NODELAY, .handler = at91rm9200_timer_interrupt };
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