From: Peter Xu <pet...@redhat.com> 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 <pet...@redhat.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Tested-by: Brian Geffon <bgef...@google.com> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Bobby Powers <bobbypow...@gmail.com> Cc: David Hildenbrand <da...@redhat.com> Cc: Denis Plotnikov <dplotni...@virtuozzo.com> Cc: "Dr . David Alan Gilbert" <dgilb...@redhat.com> Cc: Hugh Dickins <hu...@google.com> Cc: Jerome Glisse <jgli...@redhat.com> Cc: Johannes Weiner <han...@cmpxchg.org> Cc: "Kirill A . Shutemov" <kir...@shutemov.name> Cc: Martin Cracauer <craca...@cons.org> Cc: Marty McFadden <mcfadd...@llnl.gov> Cc: Matthew Wilcox <wi...@infradead.org> Cc: Maya Gokhale <gokha...@llnl.gov> Cc: Mel Gorman <mgor...@suse.de> Cc: Mike Kravetz <mike.krav...@oracle.com> Cc: Mike Rapoport <r...@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xe...@openvz.org> Link: http://lkml.kernel.org/r/20200220155353.8676-3-pet...@redhat.com Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> https://jira.sw.ru/browse/PSBM-102938 (cherry picked from commit ad415db817964e96df824e8bb1a861527f8012b6) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- mm/gup.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index f609ac36aa9a..e06aa55b65b2 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -699,6 +699,15 @@ 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); + goto out; + } continue; } } @@ -755,6 +764,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, start += page_increm * PAGE_SIZE; nr_pages -= page_increm; } while (nr_pages); +out: return i; } -- 2.25.3 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
