x86/mm: Flush lazy MMU when DEBUG_PAGEALLOC is set

When CONFIG_DEBUG_PAGEALLOC is set page table updates made by kernel_map_pages() are not made visible (via TLB flush) immediately if lazy MMU is on. In environments that support lazy MMU (e.g. Xen) this may lead to fatal page faults, for example, when zap_pte_range() needs to allocate pages in __tlb_remove_page() -> tlb_next_batch(). Signed-off-by: Boris Ostrovsky <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
CorpDK · Apr 12, 2013 · 2656460 · 2656460
1 parent 1869973
commit 2656460
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
@@ -1413,6 +1413,8 @@ void kernel_map_pages(struct page *page, int numpages, int enable)
 	 * but that can deadlock->flush only current cpu:
 	 */
 	__flush_tlb_all();
+
+	arch_flush_lazy_mmu_mode();
 }
 
 #ifdef CONFIG_HIBERNATION