All of lore.kernel.org
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Michele Ballabio <barra_cuda@katamail.com>
Cc: linux-kernel@vger.kernel.org, toralf.foerster@gmx.de,
	fweisbec@gmail.com, mingo@kernel.org,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: Bisected KVM hang on x86-32 between v3.12 and v3.13
Date: Mon, 7 Apr 2014 17:07:05 +0200	[thread overview]
Message-ID: <20140407150705.GB13658@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140407150337.GO10526@twins.programming.kicks-ass.net>

On Mon, Apr 07, 2014 at 05:03:37PM +0200, Peter Zijlstra wrote:
> So what I suspect at this point is that because i386 and x86_64 have a
> difference in current_thread_info() (i386 is stack based), we end up
> setting the TIF_NEED_RESCHED bit on the wrong stack.
> 
> Now I have some vague memories of propagating the TIF flags on stack
> switch, but I cannot remember what arch we did that for. Let me stare at
> this a little more.
> 
> Also, IFF this is the case, then the fingered patch above (and your
> suggested 'fix') aren't the real curlpit/cure but simply make it
> more/less likely to happen.
> 
> Now, Steve had a patch somewhere that would make i386 use per-cpu
> variables for current_thread_info() just like x86_64 already does I
> think. Let me go find them too.

Ohh, goodie, they're already in Linus' tree. Could you see if current
git still suffers this problem?

  reply	other threads:[~2014-04-07 15:07 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-06 15:19 Bisected KVM hang on x86-32 between v3.12 and v3.13 Michele Ballabio
2014-04-06 15:52 ` Toralf Förster
2014-04-06 17:40   ` Michele Ballabio
2014-04-07 15:03 ` Peter Zijlstra
2014-04-07 15:07   ` Peter Zijlstra [this message]
2014-04-07 18:16     ` Toralf Förster
2014-04-07 18:56       ` Peter Zijlstra
2014-04-08 12:21         ` Peter Zijlstra
2014-04-08 19:14           ` Michele Ballabio
2014-04-08 19:51             ` Michele Ballabio
2014-04-08 20:28           ` Toralf Förster
2014-04-09  9:14           ` Stefan Bader
2014-04-09  9:45             ` Peter Zijlstra
2014-04-09 14:24               ` [PATCH -stable] x86,preempt: Fix preemption for i386 Peter Zijlstra
2014-04-09 14:36                 ` Linus Torvalds
2014-04-09 19:19                   ` Greg KH
2014-04-09 19:38                     ` Peter Zijlstra
2014-04-09 19:57                       ` Greg KH
2014-05-13 23:56                       ` Greg KH
2014-04-07 18:59       ` Bisected KVM hang on x86-32 between v3.12 and v3.13 Frederic Weisbecker
2014-04-07 19:57         ` Toralf Förster
2014-04-07 22:43           ` Frederic Weisbecker
2014-04-07 19:49     ` Michele Ballabio

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=20140407150705.GB13658@twins.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=barra_cuda@katamail.com \
    --cc=fweisbec@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=toralf.foerster@gmx.de \
    /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.