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

From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dave Jones <davej@codemonkey.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Stephen Smalley <sds@tycho.nsa.gov>
Subject: Re: [GIT PULL] x86/mm changes for v4.4
Date: Thu, 5 Nov 2015 13:33:10 -0800	[thread overview]
Message-ID: <CA+55aFyC7L85SYen3Uz6e1cvH0jXzQ9_MddHJ=7PxvpOR2U23w@mail.gmail.com> (raw)
In-Reply-To: <CA+55aFyXNFu_TfmBjGedCRujoAbhqiBcia7XOtzSq0uxbVv6MA@mail.gmail.com>

On Thu, Nov 5, 2015 at 1:27 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> I suspect CONFIG_EFI_PGT_DUMP instead.
>
> Anyway, as it stands now, I think the CONFIG_DEBUG_WX option should
> not default to 'y' unless it is made more useful if it actually
> triggers. Ingo?

Actually, I guess I should have cc'd Steven Smalley too, since he's the author.

Steven, the problem is that without other debug options, the
CONFIG_DEBUG_WX option doesn't seem useful. It shows a problem, but it
doesn't actually show any information about where that issue comes
from or any other details to even *guess* at what is going on.

And if this turns out to be due to EFI wanting those permissions, what
should we do? People have talked about running the EFI callbacks in
their own private page table setup, which sounds like the right idea,
but until that actually *happens*....

                  Linus