Messages in this thread | | | Subject | Re: [PATCH] PREEMPT_RT_FULL: arm coredump fails for cpu >= 4 | From | Peter Zijlstra <> | Date | Wed, 28 Sep 2011 15:03:13 +0200 |
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On Tue, 2011-09-27 at 20:02 -0700, Frank Rowand wrote: > > ARM can not use SPLIT_PTLOCK_CPUS if PREEMPT_RT_FULL because > vectors_user_mapping() creates a VM_ALWAYSDUMP mapping of the vector page, > but no ptl->lock has been allocated for the page. An attempt to coredump > that page will result in a kernel NULL pointer dereference when > follow_page() attempts to lock the page.
> > This patch is needed only if mm-shrink-the-page-frame-to-rt-size.patch is > applied.
Yeah, vile hackery that is.. why isn't pgtable_page_ctor() called on those pages?
Not that I care too much about split_pte_lock on ARM, they're mostly all tiny machines anyway so the gain is marginal, but it would be good to find out why the pgtable constructor isn't called properly.
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