Description: mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()
References:
 https://bugzilla.redhat.com/show_bug.cgi?id=1797052
 https://www.openwall.com/lists/oss-security/2020/02/25/6
Notes:
 carnil> Introduced in ce18d171cb73 ("mm: untag user pointers in
 carnil> mmap/munmap/mremap/brk") in 5.4-rc1.
Bugs:
upstream: released (5.6-rc3) [dcde237319e626d1ec3c9d8b7613032f0fd4663a]
4.19-upstream-stable: N/A "Vulnerable code not present"
4.9-upstream-stable: N/A "Vulnerable code not present"
3.16-upstream-stable: N/A "Vulnerable code not present"
sid: released (5.5.13-1)
4.19-buster-security: N/A "Vulnerable code not present"
4.9-stretch-security: N/A "Vulnerable code not present"
3.16-jessie-security: N/A "Vulnerable code not present"