Messages in this thread | | | Date | Fri, 06 Mar 2020 13:36:35 +0000 | From | Marc Zyngier <> | Subject | Re: [patch 2/7] genirq: Add protection against unsafe usage of generic_handle_irq() |
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On 2020-03-06 13:03, Thomas Gleixner wrote: > In general calling generic_handle_irq() with interrupts disabled from > non > interrupt context is harmless. For some interrupt controllers like the > x86 > trainwrecks this is outright dangerous as it might corrupt state if an > interrupt affinity change is pending. > > Add infrastructure which allows to mark interrupts as unsafe and catch > such > usage in generic_handle_irq(). > > Reported-by: sathyanarayanan.kuppuswamy@linux.intel.com > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > include/linux/irq.h | 13 +++++++++++++ > kernel/irq/internals.h | 8 ++++++++ > kernel/irq/irqdesc.c | 6 ++++++ > kernel/irq/resend.c | 5 +++-- > 4 files changed, 30 insertions(+), 2 deletions(-) > > --- a/include/linux/irq.h > +++ b/include/linux/irq.h > @@ -211,6 +211,8 @@ struct irq_data { > * IRQD_CAN_RESERVE - Can use reservation mode > * IRQD_MSI_NOMASK_QUIRK - Non-maskable MSI quirk for affinity change > * required > + * IRQD_HANDLE_ENFORCE_IRQCTX - Enforce that handle_irq_*() is only > invoked > + * from actual interrupt context. > */ > enum { > IRQD_TRIGGER_MASK = 0xf, > @@ -234,6 +236,7 @@ enum { > IRQD_DEFAULT_TRIGGER_SET = (1 << 25), > IRQD_CAN_RESERVE = (1 << 26), > IRQD_MSI_NOMASK_QUIRK = (1 << 27), > + IRQD_HANDLE_ENFORCE_IRQCTX = (1 << 28), > }; > > #define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, > state_use_accessors) > @@ -303,6 +306,16 @@ static inline bool irqd_is_single_target > return __irqd_to_state(d) & IRQD_SINGLE_TARGET; > } > > +static inline void irqd_set_handle_enforce_irqctx(struct irq_data *d) > +{ > + __irqd_to_state(d) |= IRQD_HANDLE_ENFORCE_IRQCTX; > +} > + > +static inline bool irqd_is_handle_enforce_irqctx(struct irq_data *d) > +{ > + return __irqd_to_state(d) & IRQD_HANDLE_ENFORCE_IRQCTX; > +} > + > static inline bool irqd_is_wakeup_set(struct irq_data *d) > { > return __irqd_to_state(d) & IRQD_WAKEUP_STATE; > --- a/kernel/irq/internals.h > +++ b/kernel/irq/internals.h > @@ -425,6 +425,10 @@ static inline struct cpumask *irq_desc_g > { > return desc->pending_mask; > } > +static inline bool handle_enforce_irqctx(struct irq_data *data) > +{ > + return irqd_is_handle_enforce_irqctx(data); > +} > bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear); > #else /* CONFIG_GENERIC_PENDING_IRQ */ > static inline bool irq_can_move_pcntxt(struct irq_data *data) > @@ -451,6 +455,10 @@ static inline bool irq_fixup_move_pendin > { > return false; > } > +static inline bool handle_enforce_irqctx(struct irq_data *data) > +{ > + return false; > +} > #endif /* !CONFIG_GENERIC_PENDING_IRQ */ > > #if !defined(CONFIG_IRQ_DOMAIN) || > !defined(CONFIG_IRQ_DOMAIN_HIERARCHY) > --- a/kernel/irq/irqdesc.c > +++ b/kernel/irq/irqdesc.c > @@ -638,9 +638,15 @@ void irq_init_desc(unsigned int irq) > int generic_handle_irq(unsigned int irq) > { > struct irq_desc *desc = irq_to_desc(irq); > + struct irq_data *data; > > if (!desc) > return -EINVAL; > + > + data = irq_desc_get_irq_data(desc); > + if (WARN_ON_ONCE(!in_irq() && handle_enforce_irqctx(data))) > + return -EPERM;
It is a bit sad that there are only *two* users in the tree that actually check the return value of generic_handle_irq(). Thankfully, the WARN_ON should wake people up.
> + > generic_handle_irq_desc(desc); > return 0; > } > --- a/kernel/irq/resend.c > +++ b/kernel/irq/resend.c > @@ -72,8 +72,9 @@ void check_irq_resend(struct irq_desc *d > desc->istate &= ~IRQS_PENDING; > desc->istate |= IRQS_REPLAY; > > - if (!desc->irq_data.chip->irq_retrigger || > - !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) { > + if ((!desc->irq_data.chip->irq_retrigger || > + !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) && > + !handle_enforce_irqctx(&desc->irq_data)) { > #ifdef CONFIG_HARDIRQS_SW_RESEND > unsigned int irq = irq_desc_get_irq(desc);
Acked-by: Marc Zyngier <maz@kernel.org>
M. -- Jazz is not dead. It just smells funny...
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