Messages in this thread | | | Subject | Re: [PATCH v2] x86,nmi: Fix page faults by nmiaction if kmemcheck is enabled | From | Peter Zijlstra <> | Date | Thu, 08 Mar 2012 22:04:34 +0100 |
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On Thu, 2012-03-08 at 16:02 -0500, Don Zickus wrote: > From: Li Zhong <zhong@linux.vnet.ibm.com> > > This patch tries to fix the problem of page fault exception caused by > accessing nmiaction structure in nmi if kmemcheck is enabled. > > If kmemcheck is enabled, the memory allocated through slab are in pages > that are marked non-present, so that some checks could be done in the > page fault handling code ( e.g. whether the memory is read before > written to ). > As nmiaction is allocated in this way, so it resides in a non-present > page. Then there is a page fault while the nmi code accessing the > nmiaction structure, which would then cause a warning by > WARN_ON_ONCE(in_nmi()) in kmemcheck_fault(), called by do_page_fault(). > > v2: as Peter suggested, changed the nmiaction to use static storage. > > v3: as Peter suggested, use macro to shorten the codes. Also keep the > original usage of register_nmi_handler, so users of this call doesn't > need change. > > [simplified wrappers -dcz] > > Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> > Signed-off-by: Don Zickus <dzickus@redhat.com>
Thanks!
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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