Messages in this thread Patch in this message | | | From | Peter Xu <> | Subject | [PATCH RESEND v6 02/16] mm/gup: Fix __get_user_pages() on fault retry of hugetlb | Date | Thu, 20 Feb 2020 10:53:39 -0500 |
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When follow_hugetlb_page() returns with *locked==0, it means we've got a VM_FAULT_RETRY within the fauling process and we've released the mmap_sem. When that happens, we should stop and bail out.
Signed-off-by: Peter Xu <peterx@redhat.com> --- mm/gup.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/mm/gup.c b/mm/gup.c index 1b4411bd0042..76cb420c0fb7 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -849,6 +849,16 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, i = follow_hugetlb_page(mm, vma, pages, vmas, &start, &nr_pages, i, gup_flags, locked); + if (locked && *locked == 0) { + /* + * We've got a VM_FAULT_RETRY + * and we've lost mmap_sem. + * We must stop here. + */ + BUG_ON(gup_flags & FOLL_NOWAIT); + BUG_ON(ret != 0); + goto out; + } continue; } } -- 2.24.1
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