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authorThomas Gleixner <tglx@linutronix.de>2010-03-31 13:30:19 +0200
committerThomas Gleixner <tglx@linutronix.de>2010-03-31 15:48:38 +0200
commit753649dbc49345a73a2454c770a3f2d54d11aec6 (patch)
tree7489a4f883a1281a4874817826ebf369f7d019f0
parent2eaa9cfdf33b8d7fb7aff27792192e0019ae8fc6 (diff)
downloadlinux-2.6.34-ux500-753649dbc49345a73a2454c770a3f2d54d11aec6.tar.gz
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 <tglx@linutronix.de> Cc: Andi Kleen <andi@firstfloor.org> Cc: Linus Torvalds <torvalds@osdl.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: David Miller <davem@davemloft.net> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: stable@kernel.org
-rw-r--r--kernel/irq/manage.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 398fda155f6..704e488730a 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;