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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Dave Jones <davej@redhat.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Richard Guy Briggs <rgb@redhat.com>,
	Eric Paris <eparis@redhat.com>, Oleg Nesterov <oleg@redhat.com>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: 3.18 nohz + audit regression (Re: [PATCH] context_tracking: Restore previous state in schedule_user)
Date: Thu, 4 Dec 2014 15:23:04 +0100	[thread overview]
Message-ID: <20141204142301.GA3269@lerouge> (raw)
In-Reply-To: <CA+55aFxKr+b3t-gcSg3zsLt5Rp_cR-XLwfXstAVur=gYD8UMVA@mail.gmail.com>

On Wed, Dec 03, 2014 at 08:58:46PM -0800, Linus Torvalds wrote:
> On Wed, Dec 3, 2014 at 5:29 PM, Andy Lutomirski <luto@amacapital.net> wrote:
> >
> > So, to summarize the choices for 3.18:
> >
> > 4. This patch.
> 
> I've applied it. The alternatives look worse, and the patch doesn't
> look bad. In many ways it looks better than the old user_exit/enter
> pair, although obviously the "schedule_user()" name is kind of odd
> now. Whatever.

That doesn't look like the safest approach to me. Somehow I felt more
comfortable with exception_enter/exit on the audit function.

A few other archs use schedule_user() as well, it's likely fine but I'm
not sure how subtle their path is.

Besides, is it possible that the audit function gets called after
syscall_trace_leave() or do_notify_resume()? If so, the patch won't fix
the issue entirely.

      reply	other threads:[~2014-12-04 14:23 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-04  1:29 3.18 nohz + audit regression (Re: [PATCH] context_tracking: Restore previous state in schedule_user) Andy Lutomirski
2014-12-04  4:58 ` Linus Torvalds
2014-12-04 14:23   ` Frederic Weisbecker [this message]

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