From 2e455257d143f54b44701e947a092d513889d01c Mon Sep 17 00:00:00 2001 From: Milton Miller Date: Tue, 24 May 2011 20:34:18 +0000 Subject: [PATCH] powerpc/irq: Check desc in handle_one_irq and expand generic_handle_irq Look up the descriptor and check that it is found in handle_one_irq before checking if we are on the irq stack, and call the handler directly using the descriptor if we are on the stack. We need check irq_to_desc finds the descriptor to avoid a NULL pointer dereference. It could have failed because the number from ppc_md.get_irq was above NR_IRQS, or various exceptional conditions with sparse irqs (eg race conditions while freeing an irq if its was not shutdown in the controller). fe12bc2c99 (genirq: Uninline and sanity check generic_handle_irq()) moved generic_handle_irq out of line to allow its use by interrupt controllers in modules. However, handle_one_irq is core arch code. It already knows the details of struct irq_desc and handling irqs in the nested irq case. This will avoid the extra stack frame to return the value we don't check. Signed-off-by: Milton Miller Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/irq.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 0df2554..ac4d291 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -295,17 +295,20 @@ static inline void handle_one_irq(unsigned int irq) unsigned long saved_sp_limit; struct irq_desc *desc; + desc = irq_to_desc(irq); + if (!desc) + return; + /* Switch to the irq stack to handle this */ curtp = current_thread_info(); irqtp = hardirq_ctx[smp_processor_id()]; if (curtp == irqtp) { /* We're already on the irq stack, just handle it */ - generic_handle_irq(irq); + desc->handle_irq(irq, desc); return; } - desc = irq_to_desc(irq); saved_sp_limit = current->thread.ksp_limit; irqtp->task = curtp->task; -- 2.7.4