MFC r254191:
Match malloc(9) calls with free(9), not contigfree(9).
MFC r253969:
Do not override the ENOENT error for the empty path, or EFAULT errors
from copyins, with the relative lookup check.
Fix the mismerge in r254444, use '==' instead of '='.

Pointed out by:	jilles, John Wehle <john@feith.com>
Merge remote-tracking branch 'upstream-github/stable/9' into stable/9