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authorBrian Geffon <bgeffon@google.com>2020-05-13 17:50:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-05-14 10:00:35 -0700
commitd1564926066115fb47ca06b2b9d23ed506ca9608 (patch)
tree3f735c317ae9dc46ee144abae0d0bf80baf4e687
parent475f4dfc021c5fde69f3b7d3287bde0a50477b05 (diff)
userfaultfd: fix remap event with MREMAP_DONTUNMAP
A user is not required to set a new address when using MREMAP_DONTUNMAP as it can be used without MREMAP_FIXED. When doing so the remap event will use new_addr which may not have been set and we didn't propagate it back other then in the return value of remap_to. Because ret is always the new address it's probably more correct to use it rather than new_addr on the remap_event_complete call, and it resolves this bug. Fixes: e346b3813067d4b ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Brian Geffon <bgeffon@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: "Michael S . Tsirkin" <mst@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Sonny Rao <sonnyrao@google.com> Cc: Joel Fernandes <joel@joelfernandes.org> Link: http://lkml.kernel.org/r/20200506172158.218366-1-bgeffon@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mremap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index c881abeba0bf..6aa6ea605068 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -794,7 +794,7 @@ out:
if (locked && new_len > old_len)
mm_populate(new_addr + old_len, new_len - old_len);
userfaultfd_unmap_complete(mm, &uf_unmap_early);
- mremap_userfaultfd_complete(&uf, addr, new_addr, old_len);
+ mremap_userfaultfd_complete(&uf, addr, ret, old_len);
userfaultfd_unmap_complete(mm, &uf_unmap);
return ret;
}