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From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH] x86_64: uninline TASK_SIZE
Date: Wed, 24 Apr 2019 12:38:33 +0200	[thread overview]
Message-ID: <20190424103833.GB9642@gmail.com> (raw)
In-Reply-To: <CALCETrWtK4G7-o=pQoeyzLFTpiR9giGy2jYTU10xt6S8FsMk+Q@mail.gmail.com>


* Andy Lutomirski <luto@kernel.org> wrote:

> > Or am I missing some complication?
> 
> Seems like a great idea to me.
> 
> BTW, what the heck is up with get_gate_page()?  I'm struggling to
> understand what it's even trying to do.  If there's an architecture
> that allows a user program to mremap() or otherwise position its gate
> VMA between TASK_SIZE and TASK_SIZE_MAX, then that code is going to
> explode horribly.

I believe it was an old attempt from the times when the vsyscall area 
*didn't* have a vma, at all, and only get_gate_page() kept the mmap 
allocator from overlapping it with a user vma?

Should IMHO be entirely solved by the vma-ification of all things 
vsyscall and vdso, and we can remove this remnant.

> A whole bunch of work in this direction is here:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/log/?h=x86/fixes
> 
> It's almost entirely untested.

Please post it as patches once you are somewhat confident in the outcome 
and general direction.

Thanks,

	Ingo

  reply	other threads:[~2019-04-24 10:38 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-21 16:06 [PATCH] x86_64: uninline TASK_SIZE Alexey Dobriyan
2019-04-21 18:28 ` Ingo Molnar
2019-04-21 20:07   ` hpa
2019-04-21 21:10     ` Alexey Dobriyan
2019-04-22 10:34       ` Ingo Molnar
2019-04-22 14:30         ` Andy Lutomirski
2019-04-22 22:09           ` Alexey Dobriyan
2019-04-23  0:54             ` Andy Lutomirski
2019-04-23 11:12               ` Ingo Molnar
2019-04-23 17:21                 ` Andy Lutomirski
2019-04-24 10:38                   ` Ingo Molnar [this message]
2019-04-22 22:04         ` Alexey Dobriyan
2019-04-21 22:07   ` [PATCH v2] " Alexey Dobriyan
2019-04-22 22:40 ` [PATCH] " Linus Torvalds

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