Re: Unable to do IA64 stacktrace in early boot

From: Ingo Molnar <mingo_at_redhat.com>
Date: 2006-12-22 01:44:04
On Wed, 2006-12-20 at 22:03 -0700, Matthew Wilcox wrote:
> > mutex-debug uses DEBUG_LOCKS_WARN_ON() which indirectly calls
> > dump_stack which the IA64 unwind code (arch/ia64/kernel/unwind.c)
> calls
> > kmalloc.  The lockdep tests are run before the slab caches have been
> > allocated so cpu_cache_get is called with a NULL cachep, hence the
> > oops.
> 
> Yup.  I just debugged and fixed the same problem on parisc.  I didn't
> think to check ia64; I checked to see what x86-64 did.  Unfortunately,
> the ia64 unwind code seems a lot more subtle and more allocation-happy
> than the parisc unwind code, so I'm not sure exactly how to fix ia64.

yeah. calling kmalloc() within the unwinder is a no-no. What if the
unwind happens while kmalloc() is crashing?

	Ingo
> 

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Received on Fri Dec 22 01:47:18 2006

This archive was generated by hypermail 2.1.8 : 2006-12-22 01:47:33 EST