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authorMike Rapoport <rppt@linux.vnet.ibm.com>2017-02-24 14:58:31 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-24 17:46:55 -0800
commit96333187ab16215888f2bce01985ca5a823da8ba (patch)
tree7eb8866b6d2ab89b0bf058c3963089095049e893 /fs
parent27d02568f529e908399514dfbee8ee43bdfd5299 (diff)
downloadlinux-96333187ab16215888f2bce01985ca5a823da8ba.tar.bz2
userfaultfd_copy: return -ENOSPC in case mm has gone
In the non-cooperative userfaultfd case, the process exit may race with outstanding mcopy_atomic called by the uffd monitor. Returning -ENOSPC instead of -EINVAL when mm is already gone will allow uffd monitor to distinguish this case from other error conditions. Link: http://lkml.kernel.org/r/1485542673-24387-6-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/userfaultfd.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index b676575f2268..625b7285a37b 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1607,6 +1607,8 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
ret = mcopy_atomic(ctx->mm, uffdio_copy.dst, uffdio_copy.src,
uffdio_copy.len);
mmput(ctx->mm);
+ } else {
+ return -ENOSPC;
}
if (unlikely(put_user(ret, &user_uffdio_copy->copy)))
return -EFAULT;