All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nadav Amit <nadav.amit@gmail.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Peter Xu <peterx@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>, Yu Zhao <yuzhao@google.com>,
	Nick Piggin <npiggin@gmail.com>,
	x86@kernel.org
Subject: Re: [PATCH v2 3/5] x86/mm: check exec permissions on fault
Date: Mon, 25 Oct 2021 10:51:21 -0700	[thread overview]
Message-ID: <C30DF7E3-98B9-4985-B83B-E4FCD86A1663@gmail.com> (raw)
In-Reply-To: <37d0b84c-f6ca-15cb-8d78-b6b5a9496da7@intel.com>



> On Oct 25, 2021, at 10:45 AM, Dave Hansen <dave.hansen@intel.com> wrote:
> 
> On 10/25/21 9:19 AM, Nadav Amit wrote:
>> That was my first version, but I was concerned that perhaps there is
>> some strange scenario in which both X86_PF_WRITE and X86_PF_INSN can
>> be set. That is the reason that Peter asked you whether this is
>> something that might happen.
>> 
>> If you confirm they cannot be both set, I would the version you just
>> mentioned.
> 
> I'm pretty sure they can't be set together on any sane hardware.  A
> bonkers hypervisor or CPU could do it of course, but they'd be crazy.
> 
> BTW, feel free to add a WARN_ON_ONCE() if WRITE and INSN are both set.
> That would be a nice place to talk about the assumption.
> 

I can do that. But be aware that if the assumption is broken, it might
lead to the application getting stuck in an infinite loop of
page-faults instead of receiving SIGSEGV.


  reply	other threads:[~2021-10-25 17:51 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-21 12:21 [PATCH v2 0/5] mm/mprotect: avoid unnecessary TLB flushes Nadav Amit
2021-10-21 12:21 ` [PATCH v2 1/5] x86: Detection of Knights Landing A/D leak Nadav Amit
2021-10-26 15:54   ` Dave Hansen
2021-10-26 15:57     ` Nadav Amit
2021-10-21 12:21 ` [PATCH v2 2/5] mm: avoid unnecessary flush on change_huge_pmd() Nadav Amit
2021-10-25 10:52   ` Peter Zijlstra
2021-10-25 16:29     ` Nadav Amit
2021-10-26 16:06   ` Dave Hansen
2021-10-26 16:47     ` Nadav Amit
2021-10-26 16:53       ` Nadav Amit
2021-10-26 17:44       ` Nadav Amit
2021-10-26 18:44         ` Dave Hansen
2021-10-26 19:06           ` Nadav Amit
2021-10-26 19:40             ` Dave Hansen
2021-10-26 20:07               ` Nadav Amit
2021-10-26 20:47                 ` Dave Hansen
2021-10-21 12:21 ` [PATCH v2 3/5] x86/mm: check exec permissions on fault Nadav Amit
2021-10-25 10:59   ` Peter Zijlstra
2021-10-25 11:13     ` Andrew Cooper
2021-10-25 14:23     ` Dave Hansen
2021-10-25 14:20   ` Dave Hansen
2021-10-25 16:19     ` Nadav Amit
2021-10-25 17:45       ` Dave Hansen
2021-10-25 17:51         ` Nadav Amit [this message]
2021-10-25 18:00           ` Dave Hansen
2021-10-21 12:21 ` [PATCH v2 4/5] mm/mprotect: use mmu_gather Nadav Amit
2021-10-21 12:21 ` [PATCH v2 5/5] mm/mprotect: do not flush on permission promotion Nadav Amit
2021-10-25 11:12   ` Peter Zijlstra
2021-10-25 16:27     ` Nadav Amit
2021-10-22  3:04 ` [PATCH v2 0/5] mm/mprotect: avoid unnecessary TLB flushes Andrew Morton
2021-10-22 21:58   ` Nadav Amit
2021-10-26 16:09     ` Dave Hansen
2021-10-25 10:50   ` Peter Zijlstra
2021-10-25 16:42     ` Nadav Amit

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=C30DF7E3-98B9-4985-B83B-E4FCD86A1663@gmail.com \
    --to=nadav.amit@gmail.com \
    --cc=aarcange@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=andrew.cooper3@citrix.com \
    --cc=dave.hansen@intel.com \
    --cc=dave.hansen@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=luto@kernel.org \
    --cc=npiggin@gmail.com \
    --cc=peterx@redhat.com \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=will@kernel.org \
    --cc=x86@kernel.org \
    --cc=yuzhao@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.