LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>
Subject: Re: [RFD] x86: The future of MPX
Date: Sat, 28 Apr 2018 19:50:43 +0200	[thread overview]
Message-ID: <20180428175043.y35czmhcursyrzsy@gmail.com> (raw)
In-Reply-To: <CA+55aFwgcmpSoNh17Pbtsw8j8KzufdvroC9Rsd3K-UbTTP9qPg@mail.gmail.com>


* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Sat, Apr 28, 2018 at 2:18 AM Ingo Molnar <mingo@kernel.org> wrote:
> 
> > I just tried the MPX testcases with the latest kernel:
> 
> >   deimos:~/tip/tools/testing/selftests/x86> ./mpx-mini-test_64
> 
> They need to be run as root. They try to access
> 
>      /sys/kernel/debug/tracing/set_ftrace_pid
>      /sys/kernel/debug/tracing/trace
> 
> and that's root-only.

Indeed - but note that they are crashing as root as well here:

  root@deimos:/home/mingo/tip/tools/testing/selftests/x86# ./mpx-mini-test_64 
  [...]
  Aborted (core dumped)

... because I don't even have /sys/kernel/debug/tracing/set_ftrace_pid... :-/

That's despite having ftrace enabled.

After some digging I found out that 'set_ftrace_pid' is dependent on 
CONFIG_FUNCTION_TRACING=y (not just CONFIG_TRACING=y), which I didn't
have enabled on this kernel.

After enabling it I got the 64-bit testcase to work:

  #
  ...
  ./mpx-mini-test_64 completed successfully

But the 32-bit testcase is erroring out:

  root@deimos:/home/mingo/tip/tools/testing/selftests/x86# ./mpx-mini-test_32 
  XSAVE is supported by HW & OS
  XSAVE processor supported state mask: 0x21f
  XSAVE OS supported state mask: 0x21f
   BNDREGS: size: 64 user: 1 supervisor: 0 aligned: 0
    BNDCSR: size: 64 user: 1 supervisor: 0 aligned: 0
  executing unmaptest
  mpx dig (  1) complete, SUCCESS (       0 /    0)
  #BR status == 2, missing bounds table,kernel should have handled!!

v4.17-rc2 based kernel, so it should have the latest MPX code.

Thanks,

	Ingo

  parent reply	other threads:[~2018-04-28 17:50 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 19:37 Thomas Gleixner
2018-04-28  9:18 ` Ingo Molnar
2018-04-28 16:36   ` Linus Torvalds
2018-04-28 16:44     ` Linus Torvalds
2018-04-30  4:44       ` Dave Hansen
2018-05-02 14:00         ` Borislav Petkov
2018-05-03 16:23           ` Eric W. Biederman
2018-04-28 17:50     ` Ingo Molnar [this message]
2018-04-29  4:46       ` Eric W. Biederman

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=20180428175043.y35czmhcursyrzsy@gmail.com \
    --to=mingo@kernel.org \
    --cc=bp@alien8.de \
    --cc=dave.hansen@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [RFD] x86: The future of MPX' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).