Re: [GIT PULL] x86/mm changes for v4.4

From: Linus Torvalds
Date: Wed Nov 04 2015 - 14:26:16 EST


On Tue, Nov 3, 2015 at 3:16 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> The new CONFIG_DEBUG_WX=y warning is marked default-y if CONFIG_DEBUG_RODATA=y is
> already eanbled, as a special exception, as these bugs are hard to notice and this
> check already found several live bugs.

So this seems to be not very useful.

...
Freeing unused kernel memory: 1068K (ffffffff8bcc0000 -
ffffffff8bdcb000)
Write protecting the kernel read-only data: 12288k
Freeing unused kernel memory: 1944K (ffff88000b61a000 - ffff88000b800000)
Freeing unused kernel memory: 1372K (ffff88000baa9000 - ffff88000bc00000)
------------[ cut here ]------------
WARNING: CPU: 7 PID: 1 at arch/x86/mm/dump_pagetables.c:225
note_page+0x5dc/0x780()
x86/mm: Found insecure W+X mapping at address
ffff88000005f000/0xffff88000005f000
...
x86/mm: Checked W+X mappings: FAILED, 165660 W+X pages found.
...

because it doesn't seem to give you any idea where to look for the
issue. Those 165660 pages come out to 647MB. Odd number.

Is this *supposed* to come out clean?

Linus
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