LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	hpa@zytor.com, eranian@google.com, linux-kernel@vger.kernel.org,
	fweisbec@gmail.com, akpm@linux-foundation.org,
	tglx@linutronix.de, linux-tip-commits@vger.kernel.org,
	Robert Richter <robert.richter@amd.com>
Subject: Re: [tip:perf/core] perf/x86: Fix USER/KERNEL tagging of samples
Date: Tue, 10 Jul 2012 11:48:45 +0200
Message-ID: <20120710094845.GB14821@gmail.com> (raw)
In-Reply-To: <1341910954.3462.102.camel@twins>


* Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> On Mon, 2012-07-09 at 10:55 -0700, Linus Torvalds wrote:
> > However, it is worth pointing out that sp/bp have exactly the same
> > segment base issue. So if you do stack tracing into user mode, you
> > should really do the same thing for those. And quite frankly, at that
> > point vm86 mode and the stack segment matters in other ways than just
> > the base pointer: a 16-bit stack segment acts fundamentally
> > differently from a 32-bit one. So at that point it may well make much
> > more sense to take the approach Ingo suggests, and simply not follow
> > stack frames at all. 
> 
> Right, so I amended the patch to ignore vm86 stacks and added 
> {cs,ss}_base magic to ia32 stacks.
> 
> Ingo, do you want me to do a version where I simply bail on 
> everything if regs->{cs,ss} != {__USER_CS, __USER32_CS} || 
> regs->flags & VM ?

Only if it's really simple to do - out of morbid curiosity, to 
compare the two diffstats and such.

Thanks,

	Ingo

  reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-06  6:20 tip-bot for Peter Zijlstra
2012-07-06 16:29 ` Linus Torvalds
2012-07-06 18:12   ` Peter Zijlstra
2012-07-06 18:16     ` Linus Torvalds
2012-07-06 18:34       ` Linus Torvalds
2012-07-06 20:48         ` Peter Zijlstra
2012-07-06 20:59           ` Linus Torvalds
2012-07-09 11:23         ` Peter Zijlstra
2012-07-09 17:55           ` Linus Torvalds
2012-07-10  9:02             ` Peter Zijlstra
2012-07-10  9:48               ` Ingo Molnar [this message]
2012-07-10  9:50               ` Peter Zijlstra
2012-07-10  9:52                 ` Peter Zijlstra
2012-07-10  9:55                 ` Ingo Molnar
2012-07-31 17:57               ` [tip:perf/urgent] perf/x86: Fix USER/ KERNEL tagging of samples properly tip-bot for Peter Zijlstra
2012-07-09 18:41           ` [tip:perf/core] perf/x86: Fix USER/KERNEL tagging of samples Ingo Molnar
2012-07-10  7:54             ` Peter Zijlstra
2012-07-10  8:02               ` Ingo Molnar
2012-07-10  8:21               ` Ingo Molnar
2012-07-10  8:52                 ` Peter Zijlstra
2012-07-10  9:48                   ` Ingo Molnar
2012-07-31 18:11                     ` H. Peter Anvin

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=20120710094845.GB14821@gmail.com \
    --to=mingo@kernel.org \
    --cc=a.p.zijlstra@chello.nl \
    --cc=akpm@linux-foundation.org \
    --cc=eranian@google.com \
    --cc=fweisbec@gmail.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=robert.richter@amd.com \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    /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

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git