diff options
| -rw-r--r-- | mm/gup.c | 27 | ||||
| -rw-r--r-- | mm/hugetlb.c | 6 |
2 files changed, 25 insertions, 8 deletions
@@ -868,7 +868,10 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, if (*flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; if (*flags & FOLL_TRIED) { - VM_WARN_ON_ONCE(fault_flags & FAULT_FLAG_ALLOW_RETRY); + /* + * Note: FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_TRIED + * can co-exist + */ fault_flags |= FAULT_FLAG_TRIED; } @@ -1228,7 +1231,6 @@ retry: down_read(&mm->mmap_sem); if (!(fault_flags & FAULT_FLAG_TRIED)) { *unlocked = true; - fault_flags &= ~FAULT_FLAG_ALLOW_RETRY; fault_flags |= FAULT_FLAG_TRIED; goto retry; } @@ -1312,17 +1314,30 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, if (likely(pages)) pages += ret; start += ret << PAGE_SHIFT; + lock_dropped = true; +retry: /* * Repeat on the address that fired VM_FAULT_RETRY - * without FAULT_FLAG_ALLOW_RETRY but with - * FAULT_FLAG_TRIED. + * with both FAULT_FLAG_ALLOW_RETRY and + * FAULT_FLAG_TRIED. Note that GUP can be interrupted + * by fatal signals, so we need to check it before we + * start trying again otherwise it can loop forever. */ + + if (fatal_signal_pending(current)) + break; + *locked = 1; - lock_dropped = true; down_read(&mm->mmap_sem); + ret = __get_user_pages(tsk, mm, start, 1, flags | FOLL_TRIED, - pages, NULL, NULL); + pages, NULL, locked); + if (!*locked) { + /* Continue to retry until we succeeded */ + BUG_ON(ret != 0); + goto retry; + } if (ret != 1) { BUG_ON(ret > 1); if (!pages_done) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4d15525e9e33..0b15dc29e529 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4349,8 +4349,10 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; if (flags & FOLL_TRIED) { - VM_WARN_ON_ONCE(fault_flags & - FAULT_FLAG_ALLOW_RETRY); + /* + * Note: FAULT_FLAG_ALLOW_RETRY and + * FAULT_FLAG_TRIED can co-exist + */ fault_flags |= FAULT_FLAG_TRIED; } ret = hugetlb_fault(mm, vma, vaddr, fault_flags); |