[rfc 2/2] x86,ioapic: throw BUG instead of NULL dereference

[Cyrill Gorcunov <gorcunov@openvz.org>]

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Instead of plain NULL deref we better throw error
message with a backtrace. Actually we need more
gracious error handling here. Meanwhile leave it
as is.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---
 arch/x86/kernel/apic/io_apic.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6.git/arch/x86/kernel/apic/io_apic.c
=====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-2.6.git/arch/x86/kernel/apic/io_apic.c
@@ -503,6 +503,10 @@ static void add_pin_to_irq_node(struct i
 	}
 
 	entry = get_one_free_irq_2_pin(node);
+	if (!entry) {
+		printk(KERN_ERR "can not alloc irq_pin_list\n");
+		BUG_ON(1);
+	}
 	entry->apic = apic;
 	entry->pin = pin;