tree 3ccf3f82433f790005edd036bdaa710be90d7702
parent 8d10fa4c4c7adde131ec31ed838ee4398c02d98e
author Christopher Ferris <cferris@google.com> 1431643192 -0700
committer Christopher Ferris <cferris@google.com> 1431714773 -0700

Prevent crashes if a map cannot be created.

Under some conditions, /proc/<pid>/maps might return nothing. If we
try and unwind in this case, we'll crash. Check this case and fail
the unwind.

Add checks that no other functions try and use map_ without
checking for nullptr.

Add logging when an unwind fails so it's clear what happened.

Bug: 21162746
Change-Id: I56ce51dda0cfc9db20475a441f118108196aa07c
(cherry picked from commit 30c942cf1024bf791c28ab9b67a1f752de72248c)