Messages in this thread | | | Subject | Re: [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa | From | Benjamin Herrenschmidt <> | Date | Wed, 03 Dec 2014 07:13:10 +1100 |
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On Tue, 2014-12-02 at 13:01 +0530, Aneesh Kumar K.V wrote: > Benjamin Herrenschmidt <benh@kernel.crashing.org> writes: > > > On Fri, 2014-11-21 at 13:57 +0000, Mel Gorman wrote: > >> void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, > >> pte_t pte) > >> { > >> -#ifdef CONFIG_DEBUG_VM > >> - WARN_ON(pte_val(*ptep) & _PAGE_PRESENT); > >> -#endif > >> + /* > >> + * When handling numa faults, we already have the pte marked > >> + * _PAGE_PRESENT, but we can be sure that it is not in hpte. > >> + * Hence we can use set_pte_at for them. > >> + */ > >> + VM_WARN_ON((pte_val(*ptep) & (_PAGE_PRESENT | _PAGE_USER)) == > >> + (_PAGE_PRESENT | _PAGE_USER)); > >> + > > > > His is that going to fare with set_pte_at() called for kernel pages ? > > > > Yes, we won't capture those errors now. But is there any other debug > check i could use to capture the wrong usage of set_pte_at ?
Actually the above is fine, for some reason I mis-read the test as blowing on kernel pages, it doesn't.
We probably do need to make sure however that protnone isn't used for kernel pages.
Cheers, Ben.
> -aneesh > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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