flush_tlb_range() needs ->page_table_lock when ->mmap_sem is not held
All other callers already hold either ->mmap_sem (exclusive) or
->page_table_lock. And we need it because some page table flushing
instanced do work explicitly with ge tables.
See e.g. arch/powerpc/mm/tlb_hash32.c, flush_tlb_range() and
flush_range() in there. The same goes for uml, with a lot more
extensive playing with page tables.
Almost all callers are actually fine - flush_tlb_range() may have no
need to bother playing with page tables, but it can do so safely; again,
this caller is the sole exception - everything else either has exclusive
->mmap_sem on the mm in question, or mm->page_table_lock is held.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5f34bd8..a876871 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2277,8 +2277,8 @@
set_page_dirty(page);
list_add(&page->lru, &page_list);
}
- spin_unlock(&mm->page_table_lock);
flush_tlb_range(vma, start, end);
+ spin_unlock(&mm->page_table_lock);
mmu_notifier_invalidate_range_end(mm, start, end);
list_for_each_entry_safe(page, tmp, &page_list, lru) {
page_remove_rmap(page);