NetBSD Problem Report #52896

From www@NetBSD.org  Wed Jan  3 22:25:35 2018
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Date: Wed,  3 Jan 2018 22:25:34 +0000 (UTC)
From: coypu@sdf.org
Reply-To: coypu@sdf.org
To: gnats-bugs@NetBSD.org
Subject: amd64 kernel seems to have RWX mappings
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>Number:         52896
>Category:       port-amd64
>Synopsis:       amd64 kernel seems to have RWX mappings
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    port-amd64-maintainer
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 03 22:30:00 +0000 2018
>Closed-Date:    Fri Feb 09 09:17:44 +0000 2018
>Last-Modified:  Fri Feb 09 09:17:44 +0000 2018
>Originator:     coypu
>Release:        NetBSD 8.99.9
>Organization:
>Environment:
NetBSD localhost 8.99.9 NetBSD 8.99.9 (GENERIC) #9: Sat Dec  9 18:35:18 IST 2017  fly@localhost:/home/fly/obj/sys/arch/amd64/compile/GENERIC amd64

>Description:
# pmap 0
(omitting non RWX mappings)
FFFF800000000000 471856K read/write/exec     [ anon ]
FFFF80001CCCC000 4150224K read/write/exec     [ anon ]
FFFF80011A1C0000 524288K read/write/exec     [ pager_map ]
FFFF80013A1DA000   1200K read/write/exec     [ phys_map ]
FFFF80013EEA9000   8192K read/write/exec     [ ubc_pager ]
FFFF80013F6AD000   4096K read/write/exec     [ exec_map ]

it's possible pmap (the program) is wrong, but it seems like any executable mapping is also writable.
>How-To-Repeat:

>Fix:

>Release-Note:

>Audit-Trail:

State-Changed-From-To: open->closed
State-Changed-By: maxv@NetBSD.org
State-Changed-When: Fri, 09 Feb 2018 09:17:44 +0000
State-Changed-Why:
There is no RWX mapping on amd64. What "pmap 0" displays is the maximum permission
of a map, and by default, the maximum permission used in UVM is RWX. But the pages
are later kentered manually, and they are actually never RWX.


>Unformatted:

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