From: Oleg Nesterov <oleg@redhat.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Bobby Powers <bobbypowers@gmail.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
Borislav Petkov <bp@suse.de>, Ingo Molnar <mingo@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Fenghua Yu <fenghua.yu@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Pekka Riikonen <priikone@iki.fi>,
Quentin Casasnovas <quentin.casasnovas@oracle.com>,
Rik van Riel <riel@redhat.com>,
Suresh Siddha <sbsiddha@gmail.com>,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH] x86/fpu: always restore_xinit_state() when !use_eager_cpu()
Date: Mon, 27 Apr 2015 17:00:16 +0200 [thread overview]
Message-ID: <20150427150016.GA26871@redhat.com> (raw)
In-Reply-To: <553E4BB2.2040603@intel.com>
On 04/27, Dave Hansen wrote:
>
> On 04/26/2015 03:04 PM, Bobby Powers wrote:
>
> > The functional change was that flush_thread after f893959b only calls
> > restore_init_xstate when both !use_eager_fpu and !used_math are true.
> > drop_init_fpu (now fpu_reset_state) calls restore_init_xstate()
> > regardless of whether current used_math().
>
> This is really interesting. We were seeing some issues where the xstate
> was not getting cleared across an exec, which seemed silly, but we just
> assumed it was something that had always been there.
This is because I am stupid.
Without this Bobby's fix flush_thread() simply does nothing if a user-space
task execs (if eagerfpu).
Oleg.
next prev parent reply other threads:[~2015-04-27 15:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-26 22:04 [PATCH] x86/fpu: always restore_xinit_state() when !use_eager_cpu() Bobby Powers
2015-04-27 14:46 ` Dave Hansen
2015-04-27 15:00 ` Oleg Nesterov [this message]
2015-05-01 18:14 ` Dave Hansen
2015-04-27 14:49 ` Oleg Nesterov
2015-04-27 14:58 ` Bobby Powers
2015-04-27 15:10 ` [PATCH v2] x86/fpu: always restore_xinit_state() when use_eager_cpu() Bobby Powers
2015-04-27 15:19 ` Oleg Nesterov
2015-05-02 20:42 ` Bobby Powers
2015-05-03 17:39 ` Oleg Nesterov
2015-05-04 8:11 ` Borislav Petkov
2015-05-06 10:14 ` [tip:x86/urgent] x86/fpu: Always " tip-bot for Bobby Powers
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