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SubjectRe: [PATCH] x86/mm: Remove in_nmi() warning from 64bit implementation of vmalloc_fault()
On Wed, 24 Apr 2019, Peter Zijlstra wrote:

> > In-NMI warnings have been added to vmalloc_fault() via ebc8827f75 ("x86:
> > Barf when vmalloc and kmemcheck faults happen in NMI") back in the time
> > when our NMI entry code could not cope with nested NMIs.
> >
> > These days, it's perfectly fine to take a fault in NMI context and we
> > don't have to care about the fact that IRET from the fault handler might
> > cause NMI nesting.
> >
> > This warning has already been removed from 32bit implementation of
> > vmalloc_fault() in 6863ea0cda8 ("x86/mm: Remove in_nmi() warning from
> > vmalloc_fault()"), but 64bit version was omitted.
> >
> > Remove the bogus warning also from 64bit implementation of vmalloc_fault().
>
> Cute; did you actually trigger this?

Nope; Nicolai tripped over it while he was looking into interactions
between ftrace and pagefaults.

> > Fixes: 6863ea0cda8 ("x86/mm: Remove in_nmi() warning from vmalloc_fault()")
> > Reported-by: Nicolai Stange <nstange@suse.de>
> > Signed-off-by: Jiri Kosina <jkosina@suse.cz>
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Thanks,

--
Jiri Kosina
SUSE Labs

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