From 753649dbc49345a73a2454c770a3f2d54d11aec6 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 31 Mar 2010 13:30:19 +0200 Subject: genirq: Force MSI irq handlers to run with interrupts disabled Network folks reported that directing all MSI-X vectors of their multi queue NICs to a single core can cause interrupt stack overflows when enough interrupts fire at the same time. This is caused by the fact that we run interrupt handlers by default with interrupts enabled unless the driver reuqests the interrupt with the IRQF_DISABLED set. The NIC handlers do not set this flag, so simultaneous interrupts can nest unlimited and cause the stack overflow. The only safe counter measure is to run the interrupt handlers with interrupts disabled. We can't switch to this mode in general right now, but it is safe to do so for MSI interrupts. Force IRQF_DISABLED for MSI interrupt handlers. Signed-off-by: Thomas Gleixner Cc: Andi Kleen Cc: Linus Torvalds Cc: Andrew Morton Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Alan Cox Cc: David Miller Cc: Greg Kroah-Hartman Cc: Arnaldo Carvalho de Melo Cc: stable@kernel.org --- kernel/irq/manage.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 398fda155f6e..704e488730a5 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -757,6 +757,16 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) if (new->flags & IRQF_ONESHOT) desc->status |= IRQ_ONESHOT; + /* + * Force MSI interrupts to run with interrupts + * disabled. The multi vector cards can cause stack + * overflows due to nested interrupts when enough of + * them are directed to a core and fire at the same + * time. + */ + if (desc->msi_desc) + new->flags |= IRQF_DISABLED; + if (!(desc->status & IRQ_NOAUTOEN)) { desc->depth = 0; desc->status &= ~IRQ_DISABLED; -- cgit v1.2.3