[KDUMP] Ignore spurious IPI
miltonm at bga.com
Thu Mar 24 10:20:32 EDT 2011
On Wed, 23 Mar 2011 about 18:40:12 -0000, Takao Indoh wrote:
> Hi all,
> I found a problem that kdump(2nd kernel) sometimes hangs up. It seems
> that system panic occurs as follows.
> A pending IPI from 1st kernel comes after unmasking interrupts at the
> following point.
> asmlinkage void __init start_kernel(void)
> if (!irqs_disabled())
> printk(KERN_CRIT "start_kernel(): bug: interrupts were "
> "enabled early\n");
> early_boot_irqs_disabled = false;
> local_irq_enable(); <=======================================HERE
> Kernel tries to handle the interrupt, but some data structures are not
> initialized yet at this point. As a result, in the
> generic_smp_call_function_single_interrupt(), NULL pointer dereference
> occurs when list_replace_init() tries to access &q->list.next.
[tried to match lapic timer interrupt]
> Any comments?
So this occurs because unlike device interrupts, this vector has the action
defined statically and no per-interrupt disable on your architecture?
If so, just initialize the data structure earlier -- change
init_call_single_data from early_initcall to an explict call after the
per-cpu areas are initialized.
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