port-amd64/52696: SMAP breaks -current

[martin%NetBSD.org@localhost]

>Number:         52696
>Category:       port-amd64
>Synopsis:       SMAP breaks -current
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Nov 04 17:35:00 +0000 2017
>Originator:     Martin Husemann
>Release:        NetBSD 8.99.5
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD 8.99.5 (GENERIC) #165: Sat Nov  4 18:16:58 CET 2017 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/amd64/com
pile/GENERIC
Architecture: x86_64
Machine: amd64
>Description:

Trying to build a kernel I instantly get:

panic: prevented access to 0x800 (SMAP)
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip 0xffffffff8021cf75 cs 0x8 rflags 0x246 cr2 0x800 ilevel 0
rsp 0xffffe4011e38a850
curlwp 0xffffe4041a65f080 pid 865.1 lowest kstack 0xffffe4011e3882c0
db{3}> bt
breakpoint() at netbsd:breakpoint+0x5
vpanic() at netbsd:vpanic+0x140
snprintf() at netbsd:snprintf
trap() at netbsd:trap+0xa5f
--- trap (number 6) ---
pmap_create() at netbsd:pmap_create+0x134
uvmspace_init() at netbsd:uvmspace_init+0x84
uvmspace_alloc() at netbsd:uvmspace_alloc+0x3e
uvmspace_exec() at netbsd:uvmspace_exec+0x3f
execve_runproc() at netbsd:execve_runproc+0x4a0
execve1() at netbsd:execve1+0x3f
syscall() at netbsd:syscall+0x1bc
--- syscall (number 59) ---


>How-To-Repeat:

Try to build a kernel on -current.

>Fix:
n/a