| Message ID | 1395178858-27343-2-git-send-email-sebastian.capella@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
Hi Sebastian, On Tue, Mar 18, 2014 at 09:40:57PM +0000, Sebastian Capella wrote: > Use of tracers in local_irq_disable is causes abort loops when called > with irqs disabled using a temporary stack. Replace local_irq_disable > with raw_local_irq_disable instead to avoid tracers. Do you have any more information about these aborts? At the time we call local_irq_disable, the stack is still intact, so if the issue is simply related to having any tracers active at the call_with_stack invocation, we'd be better off disabling tracing here altogether. Will > Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org> > Cc: Russell King <linux@arm.linux.org.uk> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Robin Holt <holt@sgi.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Konstantin Khlebnikov <k.khlebnikov@samsung.com> > Cc: Steven Capper <steve.capper@linaro.org> > Cc: Stephen Warren <swarren@nvidia.com> > Cc: Tejun Heo <tj@kernel.org> > --- > arch/arm/kernel/process.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c > index 92f7b15..f58b723 100644 > --- a/arch/arm/kernel/process.c > +++ b/arch/arm/kernel/process.c > @@ -100,7 +100,7 @@ void soft_restart(unsigned long addr) > u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); > > /* Disable interrupts first */ > - local_irq_disable(); > + raw_local_irq_disable(); > local_fiq_disable(); > > /* Disable the L2 if we're the last man standing. */ > -- > 1.7.9.5 > > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Will, On 14 April 2014 03:53, Will Deacon <will.deacon@arm.com> wrote: > On Tue, Mar 18, 2014 at 09:40:57PM +0000, Sebastian Capella wrote: >> Use of tracers in local_irq_disable is causes abort loops when called >> with irqs disabled using a temporary stack. Replace local_irq_disable >> with raw_local_irq_disable instead to avoid tracers. > > Do you have any more information about these aborts? At the time we call > local_irq_disable, the stack is still intact, so if the issue is simply > related to having any tracers active at the call_with_stack invocation, we'd > be better off disabling tracing here altogether. This is specifically for when soft_restart is called in the hibernation path with tracers enabled. At that point, we've already switched to a temporary stack, and when we call local_irq_disable, we'll see this: In the local_irq_disable, it ends up calling trace_hardirqs_off (CONFIG_TRACE_IRQFLAGS_SUPPORT is enabled), which calls trace_hardirqs_off_caller which checks lockdep_recursion in the current task, but we've switched to a temporary stack with the call_with_stack, and get_current is returning NULL. This triggers a data abort, which calls trace_hardirqs_off again and so on. We originally had a patch which added a soft restart called soft_restart_noirq which avoided the irq disable. You can see the discussion here: https://patchwork.kernel.org/patch/3677591/ Thanks! Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 92f7b15..f58b723 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -100,7 +100,7 @@ void soft_restart(unsigned long addr) u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); /* Disable interrupts first */ - local_irq_disable(); + raw_local_irq_disable(); local_fiq_disable(); /* Disable the L2 if we're the last man standing. */
Use of tracers in local_irq_disable is causes abort loops when called with irqs disabled using a temporary stack. Replace local_irq_disable with raw_local_irq_disable instead to avoid tracers. Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Robin Holt <holt@sgi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Cc: Steven Capper <steve.capper@linaro.org> Cc: Stephen Warren <swarren@nvidia.com> Cc: Tejun Heo <tj@kernel.org> --- arch/arm/kernel/process.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)