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| author | Mike Kravetz <mike.kravetz@oracle.com> | 2017-02-23 02:42:58 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-23 03:41:28 +0300 |
| commit | 810a56b943e265bbabfcd5a8e54cb8d3b16cd6e4 (patch) | |
| tree | 4d95abf9e7d4efb0fa40cb6f5b1c3552e3bf2f77 /mm | |
| parent | 60d4d2d2b40e44cd36bfb6049e8d9e2055a24f8a (diff) | |
| download | linux-810a56b943e265bbabfcd5a8e54cb8d3b16cd6e4.tar.xz | |
userfaultfd: hugetlbfs: fix __mcopy_atomic_hugetlb retry/error processing
The new routine copy_huge_page_from_user() uses kmap_atomic() to map
PAGE_SIZE pages. However, this prevents page faults in the subsequent
call to copy_from_user(). This is OK in the case where the routine is
copied with mmap_sema held. However, in another case we want to allow
page faults. So, add a new argument allow_pagefault to indicate if the
routine should allow page faults.
[dan.carpenter@oracle.com: unmap the correct pointer]
Link: http://lkml.kernel.org/r/20170113082608.GA3548@mwanda
[akpm@linux-foundation.org: kunmap() takes a page*, per Hugh]
Link: http://lkml.kernel.org/r/20161216144821.5183-20-aarcange@redhat.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/hugetlb.c | 2 | ||||
| -rw-r--r-- | mm/memory.c | 13 | ||||
| -rw-r--r-- | mm/userfaultfd.c | 2 |
3 files changed, 12 insertions, 5 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index dec628b26f59..5d20af921a30 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3973,7 +3973,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, ret = copy_huge_page_from_user(page, (const void __user *) src_addr, - pages_per_huge_page(h)); + pages_per_huge_page(h), false); /* fallback to copy_from_user outside mmap_sem */ if (unlikely(ret)) { diff --git a/mm/memory.c b/mm/memory.c index 4ade940d105c..d7676a68c80a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4155,7 +4155,8 @@ void copy_user_huge_page(struct page *dst, struct page *src, long copy_huge_page_from_user(struct page *dst_page, const void __user *usr_src, - unsigned int pages_per_huge_page) + unsigned int pages_per_huge_page, + bool allow_pagefault) { void *src = (void *)usr_src; void *page_kaddr; @@ -4163,11 +4164,17 @@ long copy_huge_page_from_user(struct page *dst_page, unsigned long ret_val = pages_per_huge_page * PAGE_SIZE; for (i = 0; i < pages_per_huge_page; i++) { - page_kaddr = kmap_atomic(dst_page + i); + if (allow_pagefault) + page_kaddr = kmap(dst_page + i); + else + page_kaddr = kmap_atomic(dst_page + i); rc = copy_from_user(page_kaddr, (const void __user *)(src + i * PAGE_SIZE), PAGE_SIZE); - kunmap_atomic(page_kaddr); + if (allow_pagefault) + kunmap(dst_page + i); + else + kunmap_atomic(page_kaddr); ret_val -= (PAGE_SIZE - rc); if (rc) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index ef0495bfd17a..09976745be23 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -274,7 +274,7 @@ retry: err = copy_huge_page_from_user(page, (const void __user *)src_addr, - pages_per_huge_page(h)); + pages_per_huge_page(h), true); if (unlikely(err)) { err = -EFAULT; goto out; |