Deal with IRQs having different IRQF_DISABLED
PATCH 1/1 Deal with IRQs having different IRQF_DISABLED
handle_IRQ_event either enables IRQs or leaves them disabled for the entire chain. However, there is nothing in request_irq or setup_irq which ensures that all IRQs in a chain will have the same IRQF_DISABLED.
This seems like a bug to me. Below are two possible fixes - enable/disable IRQs for each action or refuse to register an IRQ if there is a mismatched IRQF_DISABLED.
Signature · 69 lines
Work email - jdike at linux dot intel dot com Refuse to register an IRQ if it has a mismatched IRQF_DISABLED with what's already in the IRQ chain. Signed-off-by: Jeff Dike <[email protected]> -- kernel/irq/manage.c | 8 ++++++++ 1 file changed, 8 insertions(+) Index: linux-2.6.21-mm/kernel/irq/manage.c =================================================================== --- linux-2.6.21-mm.orig/kernel/irq/manage.c 2007-05-23 09:01:16.000000000 -0400 +++ linux-2.6.21-mm/kernel/irq/manage.c 2007-05-23 09:02:28.000000000 -0400 @@ -301,6 +301,14 @@ int setup_irq(unsigned int irq, struct i goto mismatch; } + /* + * Handlers must agree on disabling IRQs since + * handle_IRQ_event leaves IRQs either on or off for + * the entire chain. + */ + if ((old->flags ^ new->flags) & IRQF_DISABLED) + goto mismatch; + #if defined(CONFIG_IRQ_PER_CPU) /* All handlers must agree on per-cpuness */ if ((old->flags & IRQF_PERCPU) != Move the enabling/disabling of IRQs into the loop so that actions with differing IRQF_DISABLED get the IRQ enabling that they asked for. Signed-off-by: Jeff Dike <[email protected]> -- kernel/irq/handle.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) Index: linux-2.6.21-mm/kernel/irq/handle.c =================================================================== --- linux-2.6.21-mm.orig/kernel/irq/handle.c 2007-05-16 18:21:18.000000000 -0400 +++ linux-2.6.21-mm/kernel/irq/handle.c 2007-05-23 09:02:57.000000000 -0400 @@ -133,20 +133,21 @@ irqreturn_t handle_IRQ_event(unsigned in handle_dynamic_tick(action); - if (!(action->flags & IRQF_DISABLED)) - local_irq_enable_in_hardirq(); - do { + if (!(action->flags & IRQF_DISABLED)) + local_irq_enable_in_hardirq(); + ret = action->handler(irq, action->dev_id); if (ret == IRQ_HANDLED) status |= action->flags; retval |= ret; action = action->next; + + local_irq_disable(); } while (action); if (status & IRQF_SAMPLE_RANDOM) add_interrupt_randomness(irq); - local_irq_disable(); return retval; }