tree 4058875667899bec12774f4843a0e123aa7c4b6c
parent df2f5fbe6f3d3937c3caf95138e43ee15f6d8497
author Dimitry Ivanov <dimitry@google.com> 1452885215 -0800
committer Dimitry Ivanov <dimitry@google.com> 1453352267 -0800

Do not unmap reserved region on dlclose

dlclose used to unmap the part of the reserved region
for ANDROID_DLEXT_RESERVED_ADDRESS that was neccessary
to map PT_LOAD segments. With this change dlclose
replaces mapped PT_LOAD segments with a PROT_NONE,
MAP_ANONYMOUS | MAP_NORESERVE.

Previously caller was unmapping the reserved region after
the failed dlclose which led to race condition when someone
else reused the region freed by dlclose but before the unmap
by the chromium code.

Bug: http://code.google.com/p/chromium/issues/detail?id=568880
Change-Id: I0f5eaa2bf6641f83dde469b631c518482acc59a2