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?
next prev parent 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 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
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