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authorAndrea Arcangeli <aarcange@redhat.com>2019-02-01 14:20:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-02-01 15:46:23 -0800
commit1ac25013fb9e4ed595cd608a406191e93520881e (patch)
tree7be7a10047d58317e275f2028b112515dc6a9c43
parent36c0f7f0f89984bb21e6d0f92d776faf7be73096 (diff)
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mm/hugetlb.c: teach follow_hugetlb_page() to handle FOLL_NOWAIT
hugetlb needs the same fix as faultin_nopage (which was applied in commit 96312e61282a ("mm/gup.c: teach get_user_pages_unlocked to handle FOLL_NOWAIT")) or KVM hangs because it thinks the mmap_sem was already released by hugetlb_fault() if it returned VM_FAULT_RETRY, but it wasn't in the FOLL_NOWAIT case. Link: http://lkml.kernel.org/r/20190109020203.26669-2-aarcange@redhat.com Fixes: ce53053ce378 ("kvm: switch get_user_page_nowait() to get_user_pages_unlocked()") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/hugetlb.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index df2e7dd5ff17..afef61656c1e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4268,7 +4268,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
break;
}
if (ret & VM_FAULT_RETRY) {
- if (nonblocking)
+ if (nonblocking &&
+ !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
*nonblocking = 0;
*nr_pages = 0;
/*