On Wed, 5 Sep 2018 14:35:11 -0700 Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote: > > so perhaps we could put some > > stopgap workaround into that site and add a runtime warning into the > > put_page() code somewhere to detect puttage of huge pages from hardirq > > and softirq contexts. > > I think we would add the warning/etc at free_huge_page. The issue would > only apply to hugetlb pages, not THP. > > But, the more I think about it the more I think Aneesh's patch to do > spin_lock/unlock_irqsave is the right way to go. Currently, we only > know of one place where a put_page of hugetlb pages is done from softirq > context. So, we could take the spin_lock/unlock_bh as Matthew suggested. > When the powerpc iommu code was added, I doubt this was taken into account. > I would be afraid of someone adding put_page from hardirq context. Me too. If we're going to do this, surely we should make hugepages behave in the same fashion as PAGE_SIZE pages.
