> It should not as __check_irq_replay() should always be called
> with interrupts hard disabled... Do you see any code path
> where that is not the case ?
More specifically, your backtrace seems to indicate that
__check_irq_repay() was called from arch_local_irq_restore() which
should have done this before calling __check_irq_replay():
if (unlikely(irq_happened != PACA_IRQ_HARD_DIS))
__hard_irq_disable();
Now, the only possibility that I can see for an interrupt to come in
and trip the problem you observed would be if for some reason we
had irq_happened set to PACA_IRQ_HARD_DIS while interrupts were
not hard disabled.
Can you try if removing the test (and thus unconditionally calling
__hard_irq_disable()) fixes the problem for you ?
If that is the case, then we need to audit the code to figure out how we
can end up with that bit in irq_happened set and interrupts hard
enabled.
Something like may_hard_irq_enable() shouldn't cause it since it should
only be called while hard disabled but adding a check in there might be
worth it (something like WARN_ON(mfmsr() & MSR_EE)).
Cheers,
Ben.
> Cheers,
> Ben.
>
> > Signed-off-by: Wang Sheng-Hui <shh...@gmail.com>
> > ---
> > arch/powerpc/kernel/irq.c | 46
> > +++++++++++++++++++++++++++++---------------
> > 1 files changed, 30 insertions(+), 16 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> > index 5ec1b23..3d48b23 100644
> > --- a/arch/powerpc/kernel/irq.c
> > +++ b/arch/powerpc/kernel/irq.c
> > @@ -137,15 +137,17 @@ static inline notrace int
> > decrementer_check_overflow(void)
> > */
> > notrace unsigned int __check_irq_replay(void)
> > {
> > + unsigned int ret_val;
> > /*
> > * We use local_paca rather than get_paca() to avoid all
> > * the debug_smp_processor_id() business in this low level
> > * function
> > */
> > - unsigned char happened = local_paca->irq_happened;
> > + unsigned char happened, irq_happened;
> > + happened = irq_happened = local_paca->irq_happened;
> >
> > /* Clear bit 0 which we wouldn't clear otherwise */
> > - local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
> > + irq_happened &= ~PACA_IRQ_HARD_DIS;
> >
> > /*
> > * Force the delivery of pending soft-disabled interrupts on PS3.
> > @@ -161,33 +163,45 @@ notrace unsigned int __check_irq_replay(void)
> > * decrementer itself rather than the paca irq_happened field
> > * in case we also had a rollover while hard disabled
> > */
> > - local_paca->irq_happened &= ~PACA_IRQ_DEC;
> > - if (decrementer_check_overflow())
> > - return 0x900;
> > + irq_happened &= ~PACA_IRQ_DEC;
> > + if (decrementer_check_overflow()) {
> > + ret_val = 0x900;
> > + goto replay;
> > + }
> >
> > /* Finally check if an external interrupt happened */
> > - local_paca->irq_happened &= ~PACA_IRQ_EE;
> > - if (happened & PACA_IRQ_EE)
> > - return 0x500;
> > + irq_happened &= ~PACA_IRQ_EE;
> > + if (happened & PACA_IRQ_EE) {
> > + ret_val = 0x500;
> > + goto replay;
> > + }
> >
> > #ifdef CONFIG_PPC_BOOK3E
> > /* Finally check if an EPR external interrupt happened
> > * this bit is typically set if we need to handle another
> > * "edge" interrupt from within the MPIC "EPR" handler
> > */
> > - local_paca->irq_happened &= ~PACA_IRQ_EE_EDGE;
> > - if (happened & PACA_IRQ_EE_EDGE)
> > - return 0x500;
> > + irq_happened &= ~PACA_IRQ_EE_EDGE;
> > + if (happened & PACA_IRQ_EE_EDGE) {
> > + ret_val = 0x500;
> > + goto replay;
> > + }
> >
> > - local_paca->irq_happened &= ~PACA_IRQ_DBELL;
> > - if (happened & PACA_IRQ_DBELL)
> > - return 0x280;
> > + irq_happened &= ~PACA_IRQ_DBELL;
> > + if (happened & PACA_IRQ_DBELL) {
> > + ret_val = 0x280;
> > + goto replay;
> > + }
> > #endif /* CONFIG_PPC_BOOK3E */
> >
> > /* There should be nothing left ! */
> > - BUG_ON(local_paca->irq_happened != 0);
> > + BUG_ON(irq_happened != 0);
> > + ret_val = 0;
> >
> > - return 0;
> > +replay:
> > + local_paca->irq_happened = irq_happened;
> > +
> > + return ret_val;
> > }
> >
> > notrace void arch_local_irq_restore(unsigned long en)
>
>
> --
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