The pagemap_open function in fs/proc/task_mmu.c in the Linux kernel before 3.19.3, as used in Android 6.0.1 before 2016-03-01, allows local users to obtain sensitive physical-address information by reading a pagemap file, aka Android internal bug 25739721.
https://github.com/torvalds/linux/commit/ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce
http://www.securityfocus.com/bid/84265
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.19.3
http://source.android.com/security/bulletin/2016-03-01.html
http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html