diff options
| -rw-r--r-- | arch/arm64/include/asm/pgtable.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index e65083ec35cb..43457940a388 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -83,11 +83,21 @@ static inline void queue_pte_barriers(void) #define __HAVE_ARCH_ENTER_LAZY_MMU_MODE static inline void arch_enter_lazy_mmu_mode(void) { + /* + * lazy_mmu_mode is not supposed to permit nesting. But in practice this + * does happen with CONFIG_DEBUG_PAGEALLOC, where a page allocation + * inside a lazy_mmu_mode section (such as zap_pte_range()) will change + * permissions on the linear map with apply_to_page_range(), which + * re-enters lazy_mmu_mode. So we tolerate nesting in our + * implementation. The first call to arch_leave_lazy_mmu_mode() will + * flush and clear the flag such that the remainder of the work in the + * outer nest behaves as if outside of lazy mmu mode. This is safe and + * keeps tracking simple. + */ + if (in_interrupt()) return; - VM_WARN_ON(test_thread_flag(TIF_LAZY_MMU)); - set_thread_flag(TIF_LAZY_MMU); } |