tree 00ea236b05ba155626a54889149770fdfa8615b1
parent 1ec7fc8fd7ae4ac2c677046abf7dec269619f036
author Brian Geffon <bgeffon@google.com> 1589417444 -0700
committer Tim Zimmermann <tim@linux4.de> 1721966656 +0200
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UPSTREAM: 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>
(cherry picked from commit d1564926066115fb47ca06b2b9d23ed506ca9608)

Bug: 176847609
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Change-Id: I7a20139ee14a2c9124b74310d7c0324c11009087