Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-31 Thread Andy Lutomirski
On Fri, Jan 30, 2015 at 7:12 PM, Andy Lutomirski wrote: > On Fri, Jan 30, 2015 at 5:28 PM, Sasha Levin wrote: >> On 01/30/2015 02:57 PM, Sasha Levin wrote: >>> On 01/28/2015 04:02 PM, Andy Lutomirski wrote: On Wed, Jan 28, 2015 at 9:48 AM, Paul E. McKenney wrote: > On Wed, Jan 28,

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-30 Thread Andy Lutomirski
On Fri, Jan 30, 2015 at 5:28 PM, Sasha Levin wrote: > On 01/30/2015 02:57 PM, Sasha Levin wrote: >> On 01/28/2015 04:02 PM, Andy Lutomirski wrote: >>> On Wed, Jan 28, 2015 at 9:48 AM, Paul E. McKenney >>> wrote: On Wed, Jan 28, 2015 at 08:33:06AM -0800, Andy Lutomirski wrote: > On Fri, J

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-30 Thread Sasha Levin
On 01/30/2015 02:57 PM, Sasha Levin wrote: > On 01/28/2015 04:02 PM, Andy Lutomirski wrote: >> On Wed, Jan 28, 2015 at 9:48 AM, Paul E. McKenney >> wrote: >>> On Wed, Jan 28, 2015 at 08:33:06AM -0800, Andy Lutomirski wrote: On Fri, Jan 23, 2015 at 5:25 PM, Andy Lutomirski wrote: >

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-30 Thread Sasha Levin
On 01/28/2015 04:02 PM, Andy Lutomirski wrote: > On Wed, Jan 28, 2015 at 9:48 AM, Paul E. McKenney > wrote: >> On Wed, Jan 28, 2015 at 08:33:06AM -0800, Andy Lutomirski wrote: >>> On Fri, Jan 23, 2015 at 5:25 PM, Andy Lutomirski >>> wrote: On Fri, Jan 23, 2015 at 12:48 PM, Sasha Levin >>>

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-28 Thread Andy Lutomirski
On Wed, Jan 28, 2015 at 9:48 AM, Paul E. McKenney wrote: > On Wed, Jan 28, 2015 at 08:33:06AM -0800, Andy Lutomirski wrote: >> On Fri, Jan 23, 2015 at 5:25 PM, Andy Lutomirski wrote: >> > On Fri, Jan 23, 2015 at 12:48 PM, Sasha Levin >> > wrote: >> >> On 01/23/2015 01:34 PM, Andy Lutomirski wro

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-28 Thread Andy Lutomirski
On Fri, Jan 23, 2015 at 5:25 PM, Andy Lutomirski wrote: > On Fri, Jan 23, 2015 at 12:48 PM, Sasha Levin wrote: >> On 01/23/2015 01:34 PM, Andy Lutomirski wrote: >>> On Fri, Jan 23, 2015 at 10:04 AM, Borislav Petkov wrote: On Fri, Jan 23, 2015 at 09:58:01AM -0800, Andy Lutomirski wrote:

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-28 Thread Paul E. McKenney
On Wed, Jan 28, 2015 at 08:33:06AM -0800, Andy Lutomirski wrote: > On Fri, Jan 23, 2015 at 5:25 PM, Andy Lutomirski wrote: > > On Fri, Jan 23, 2015 at 12:48 PM, Sasha Levin > > wrote: > >> On 01/23/2015 01:34 PM, Andy Lutomirski wrote: > >>> On Fri, Jan 23, 2015 at 10:04 AM, Borislav Petkov wro

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-23 Thread Andy Lutomirski
On Fri, Jan 23, 2015 at 12:48 PM, Sasha Levin wrote: > On 01/23/2015 01:34 PM, Andy Lutomirski wrote: >> On Fri, Jan 23, 2015 at 10:04 AM, Borislav Petkov wrote: >>> On Fri, Jan 23, 2015 at 09:58:01AM -0800, Andy Lutomirski wrote: > [ 543.999079] Call Trace: > [ 543.999079] dump_stack (

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-23 Thread Sasha Levin
On 01/23/2015 01:34 PM, Andy Lutomirski wrote: > On Fri, Jan 23, 2015 at 10:04 AM, Borislav Petkov wrote: >> On Fri, Jan 23, 2015 at 09:58:01AM -0800, Andy Lutomirski wrote: [ 543.999079] Call Trace: [ 543.999079] dump_stack (lib/dump_stack.c:52) [ 543.999079] lockdep_rcu_suspici

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-23 Thread Andy Lutomirski
On Fri, Jan 23, 2015 at 10:04 AM, Borislav Petkov wrote: > On Fri, Jan 23, 2015 at 09:58:01AM -0800, Andy Lutomirski wrote: >> > [ 543.999079] Call Trace: >> > [ 543.999079] dump_stack (lib/dump_stack.c:52) >> > [ 543.999079] lockdep_rcu_suspicious (kernel/locking/lockdep.c:4259) >> > [ 543.99

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-23 Thread Borislav Petkov
On Fri, Jan 23, 2015 at 09:58:01AM -0800, Andy Lutomirski wrote: > > [ 543.999079] Call Trace: > > [ 543.999079] dump_stack (lib/dump_stack.c:52) > > [ 543.999079] lockdep_rcu_suspicious (kernel/locking/lockdep.c:4259) > > [ 543.999079] atomic_notifier_call_chain (include/linux/rcupdate.h:892

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-23 Thread Andy Lutomirski
On Thu, Jan 22, 2015 at 1:52 PM, Sasha Levin wrote: > On 11/21/2014 04:26 PM, Andy Lutomirski wrote: >> We currently pretend that IST context is like standard exception >> context, but this is incorrect. IST entries from userspace are like >> standard exceptions except that they use per-cpu stack

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-22 Thread Sasha Levin
On 11/21/2014 04:26 PM, Andy Lutomirski wrote: > We currently pretend that IST context is like standard exception > context, but this is incorrect. IST entries from userspace are like > standard exceptions except that they use per-cpu stacks, so they are > atomic. IST entries from kernel space ar

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-05 Thread Andy Lutomirski
On Mon, Jan 5, 2015 at 1:46 PM, Tony Luck wrote: > On Wed, Dec 10, 2014 at 4:24 PM, Andy Lutomirski wrote: >> I think you need ist_begin_non_atomic() before local_irq_enable() and >> ist_end_non_atomic() after local_irq_disable(). Otherwise it should >> be good. > > In your x86/paranoid branch y

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2015-01-05 Thread Tony Luck
On Wed, Dec 10, 2014 at 4:24 PM, Andy Lutomirski wrote: > I think you need ist_begin_non_atomic() before local_irq_enable() and > ist_end_non_atomic() after local_irq_disable(). Otherwise it should > be good. In your x86/paranoid branch you added: prev_state = ist_enter(regs); ..

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-12-10 Thread Andy Lutomirski
On Wed, Dec 10, 2014 at 4:22 PM, Tony Luck wrote: > On Tue, Nov 25, 2014 at 10:58 AM, Borislav Petkov wrote: >> On Mon, Nov 24, 2014 at 03:52:10PM -0800, Andy Lutomirski wrote: >>> Dunno. Tony and Borislav -- when do you want the IST stack switching >>> stuff? >> >> I'd leave that up to Tony and

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-12-10 Thread Tony Luck
On Tue, Nov 25, 2014 at 10:58 AM, Borislav Petkov wrote: > On Mon, Nov 24, 2014 at 03:52:10PM -0800, Andy Lutomirski wrote: >> Dunno. Tony and Borislav -- when do you want the IST stack switching >> stuff? > > I'd leave that up to Tony and his testbench. I mean, we can hammer on > it as much as we

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-12-01 Thread Paul E. McKenney
On Thu, Nov 27, 2014 at 03:03:22PM +0800, Lai Jiangshan wrote: > > > > > Signed-off-by: Paul E. McKenney > > Reviewed-by: Lai Jiangshan Thank you, recorded! > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index 8749f43f3f05..fc0236992655 100644 > > --- a/kernel/rcu/tree.c > > +++

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-26 Thread Lai Jiangshan
> > Signed-off-by: Paul E. McKenney > Reviewed-by: Lai Jiangshan > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index 8749f43f3f05..fc0236992655 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -759,39 +759,71 @@ void rcu_irq_enter(void) > /** > * rcu_nmi_enter -

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-25 Thread Paul E. McKenney
On Tue, Nov 25, 2014 at 07:58:03PM +0100, Borislav Petkov wrote: > On Mon, Nov 24, 2014 at 03:52:10PM -0800, Andy Lutomirski wrote: > > Dunno. Tony and Borislav -- when do you want the IST stack switching > > stuff? > > I'd leave that up to Tony and his testbench. I mean, we can hammer on > it as

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-25 Thread Borislav Petkov
On Mon, Nov 24, 2014 at 03:52:10PM -0800, Andy Lutomirski wrote: > Dunno. Tony and Borislav -- when do you want the IST stack switching > stuff? I'd leave that up to Tony and his testbench. I mean, we can hammer on it as much as we can and it can pass all testing locally but the real fun starts on

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-25 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 03:50:58PM -0800, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 03:35:55PM -0800, Andy Lutomirski wrote: > > On Mon, Nov 24, 2014 at 3:31 PM, Paul E. McKenney > > wrote: > > > On Mon, Nov 24, 2014 at 02:57:54PM -0800, Paul E. McKenney wrote: > > >> On Mon, Nov 24, 2014

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Andy Lutomirski
On Mon, Nov 24, 2014 at 3:50 PM, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 03:35:55PM -0800, Andy Lutomirski wrote: >> On Mon, Nov 24, 2014 at 3:31 PM, Paul E. McKenney >> wrote: >> > On Mon, Nov 24, 2014 at 02:57:54PM -0800, Paul E. McKenney wrote: >> >> On Mon, Nov 24, 2014 at 02:36:18P

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 03:35:55PM -0800, Andy Lutomirski wrote: > On Mon, Nov 24, 2014 at 3:31 PM, Paul E. McKenney > wrote: > > On Mon, Nov 24, 2014 at 02:57:54PM -0800, Paul E. McKenney wrote: > >> On Mon, Nov 24, 2014 at 02:36:18PM -0800, Andy Lutomirski wrote: > >> > On Mon, Nov 24, 2014 at 2

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Andy Lutomirski
On Mon, Nov 24, 2014 at 3:31 PM, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 02:57:54PM -0800, Paul E. McKenney wrote: >> On Mon, Nov 24, 2014 at 02:36:18PM -0800, Andy Lutomirski wrote: >> > On Mon, Nov 24, 2014 at 2:34 PM, Paul E. McKenney >> > wrote: >> > > On Mon, Nov 24, 2014 at 01:35:

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 02:57:54PM -0800, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 02:36:18PM -0800, Andy Lutomirski wrote: > > On Mon, Nov 24, 2014 at 2:34 PM, Paul E. McKenney > > wrote: > > > On Mon, Nov 24, 2014 at 01:35:01PM -0800, Paul E. McKenney wrote: > > [ . . . ] > > > > And

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 02:36:18PM -0800, Andy Lutomirski wrote: > On Mon, Nov 24, 2014 at 2:34 PM, Paul E. McKenney > wrote: > > On Mon, Nov 24, 2014 at 01:35:01PM -0800, Paul E. McKenney wrote: [ . . . ] > > And the following Promela model claims that your approach works. > > Should I trust it

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Andy Lutomirski
On Mon, Nov 24, 2014 at 2:34 PM, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 01:35:01PM -0800, Paul E. McKenney wrote: >> On Mon, Nov 24, 2014 at 01:02:51PM -0800, Andy Lutomirski wrote: >> > On Mon, Nov 24, 2014 at 12:54 PM, Paul E. McKenney >> > wrote: >> > > On Mon, Nov 24, 2014 at 12:22

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 01:35:01PM -0800, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 01:02:51PM -0800, Andy Lutomirski wrote: > > On Mon, Nov 24, 2014 at 12:54 PM, Paul E. McKenney > > wrote: > > > On Mon, Nov 24, 2014 at 12:22:13PM -0800, Andy Lutomirski wrote: > > >> On Sat, Nov 22, 2014

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 01:02:51PM -0800, Andy Lutomirski wrote: > On Mon, Nov 24, 2014 at 12:54 PM, Paul E. McKenney > wrote: > > On Mon, Nov 24, 2014 at 12:22:13PM -0800, Andy Lutomirski wrote: > >> On Sat, Nov 22, 2014 at 3:41 PM, Paul E. McKenney > >> wrote: > >> > On Fri, Nov 21, 2014 at 09:

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 12:54:41PM -0800, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 12:22:13PM -0800, Andy Lutomirski wrote: > > On Sat, Nov 22, 2014 at 3:41 PM, Paul E. McKenney > > wrote: > > > On Fri, Nov 21, 2014 at 09:53:29PM -0800, Andy Lutomirski wrote: > > >> On Fri, Nov 21, 2014 a

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Andy Lutomirski
On Mon, Nov 24, 2014 at 12:54 PM, Paul E. McKenney wrote: > On Mon, Nov 24, 2014 at 12:22:13PM -0800, Andy Lutomirski wrote: >> On Sat, Nov 22, 2014 at 3:41 PM, Paul E. McKenney >> wrote: >> > On Fri, Nov 21, 2014 at 09:53:29PM -0800, Andy Lutomirski wrote: >> >> On Fri, Nov 21, 2014 at 8:20 PM,

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Paul E. McKenney
On Mon, Nov 24, 2014 at 12:22:13PM -0800, Andy Lutomirski wrote: > On Sat, Nov 22, 2014 at 3:41 PM, Paul E. McKenney > wrote: > > On Fri, Nov 21, 2014 at 09:53:29PM -0800, Andy Lutomirski wrote: > >> On Fri, Nov 21, 2014 at 8:20 PM, Paul E. McKenney > >> wrote: > >> > On Fri, Nov 21, 2014 at 06:0

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Andy Lutomirski
On Sat, Nov 22, 2014 at 3:41 PM, Paul E. McKenney wrote: > On Fri, Nov 21, 2014 at 09:53:29PM -0800, Andy Lutomirski wrote: >> On Fri, Nov 21, 2014 at 8:20 PM, Paul E. McKenney >> wrote: >> > On Fri, Nov 21, 2014 at 06:00:14PM -0800, Andy Lutomirski wrote: >> >> On Fri, Nov 21, 2014 at 3:38 PM, P

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-24 Thread Andy Lutomirski
On Sat, Nov 22, 2014 at 9:20 AM, Borislav Petkov wrote: > On Fri, Nov 21, 2014 at 01:26:08PM -0800, Andy Lutomirski wrote: >> We currently pretend that IST context is like standard exception >> context, but this is incorrect. IST entries from userspace are like >> standard exceptions except that

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-22 Thread Paul E. McKenney
On Fri, Nov 21, 2014 at 09:53:29PM -0800, Andy Lutomirski wrote: > On Fri, Nov 21, 2014 at 8:20 PM, Paul E. McKenney > wrote: > > On Fri, Nov 21, 2014 at 06:00:14PM -0800, Andy Lutomirski wrote: > >> On Fri, Nov 21, 2014 at 3:38 PM, Paul E. McKenney > >> wrote: > >> > On Fri, Nov 21, 2014 at 03:0

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-22 Thread Borislav Petkov
On Fri, Nov 21, 2014 at 01:26:08PM -0800, Andy Lutomirski wrote: > We currently pretend that IST context is like standard exception > context, but this is incorrect. IST entries from userspace are like > standard exceptions except that they use per-cpu stacks, so they are > atomic. IST entries fr

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Andy Lutomirski
On Fri, Nov 21, 2014 at 8:20 PM, Paul E. McKenney wrote: > On Fri, Nov 21, 2014 at 06:00:14PM -0800, Andy Lutomirski wrote: >> On Fri, Nov 21, 2014 at 3:38 PM, Paul E. McKenney >> wrote: >> > On Fri, Nov 21, 2014 at 03:06:48PM -0800, Andy Lutomirski wrote: >> >> On Fri, Nov 21, 2014 at 2:55 PM, P

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Paul E. McKenney
On Fri, Nov 21, 2014 at 06:00:14PM -0800, Andy Lutomirski wrote: > On Fri, Nov 21, 2014 at 3:38 PM, Paul E. McKenney > wrote: > > On Fri, Nov 21, 2014 at 03:06:48PM -0800, Andy Lutomirski wrote: > >> On Fri, Nov 21, 2014 at 2:55 PM, Paul E. McKenney > >> wrote: > >> > On Fri, Nov 21, 2014 at 02:1

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Andy Lutomirski
On Fri, Nov 21, 2014 at 3:38 PM, Paul E. McKenney wrote: > On Fri, Nov 21, 2014 at 03:06:48PM -0800, Andy Lutomirski wrote: >> On Fri, Nov 21, 2014 at 2:55 PM, Paul E. McKenney >> wrote: >> > On Fri, Nov 21, 2014 at 02:19:17PM -0800, Andy Lutomirski wrote: >> >> On Fri, Nov 21, 2014 at 2:07 PM, P

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Paul E. McKenney
On Fri, Nov 21, 2014 at 03:06:48PM -0800, Andy Lutomirski wrote: > On Fri, Nov 21, 2014 at 2:55 PM, Paul E. McKenney > wrote: > > On Fri, Nov 21, 2014 at 02:19:17PM -0800, Andy Lutomirski wrote: > >> On Fri, Nov 21, 2014 at 2:07 PM, Paul E. McKenney > >> wrote: > >> > On Fri, Nov 21, 2014 at 01:3

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Andy Lutomirski
On Fri, Nov 21, 2014 at 2:55 PM, Paul E. McKenney wrote: > On Fri, Nov 21, 2014 at 02:19:17PM -0800, Andy Lutomirski wrote: >> On Fri, Nov 21, 2014 at 2:07 PM, Paul E. McKenney >> wrote: >> > On Fri, Nov 21, 2014 at 01:32:50PM -0800, Andy Lutomirski wrote: >> >> On Fri, Nov 21, 2014 at 1:26 PM, A

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Paul E. McKenney
On Fri, Nov 21, 2014 at 02:19:17PM -0800, Andy Lutomirski wrote: > On Fri, Nov 21, 2014 at 2:07 PM, Paul E. McKenney > wrote: > > On Fri, Nov 21, 2014 at 01:32:50PM -0800, Andy Lutomirski wrote: > >> On Fri, Nov 21, 2014 at 1:26 PM, Andy Lutomirski > >> wrote: > >> > We currently pretend that IS

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Andy Lutomirski
On Fri, Nov 21, 2014 at 2:07 PM, Paul E. McKenney wrote: > On Fri, Nov 21, 2014 at 01:32:50PM -0800, Andy Lutomirski wrote: >> On Fri, Nov 21, 2014 at 1:26 PM, Andy Lutomirski wrote: >> > We currently pretend that IST context is like standard exception >> > context, but this is incorrect. IST en

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Frederic Weisbecker
On Fri, Nov 21, 2014 at 02:07:04PM -0800, Paul E. McKenney wrote: > On Fri, Nov 21, 2014 at 01:32:50PM -0800, Andy Lutomirski wrote: > > On Fri, Nov 21, 2014 at 1:26 PM, Andy Lutomirski > > wrote: > > > We currently pretend that IST context is like standard exception > > > context, but this is in

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Paul E. McKenney
On Fri, Nov 21, 2014 at 01:32:50PM -0800, Andy Lutomirski wrote: > On Fri, Nov 21, 2014 at 1:26 PM, Andy Lutomirski wrote: > > We currently pretend that IST context is like standard exception > > context, but this is incorrect. IST entries from userspace are like > > standard exceptions except th

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Paul E. McKenney
On Fri, Nov 21, 2014 at 01:26:08PM -0800, Andy Lutomirski wrote: > We currently pretend that IST context is like standard exception > context, but this is incorrect. IST entries from userspace are like > standard exceptions except that they use per-cpu stacks, so they are > atomic. IST entries fr

Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Andy Lutomirski
On Fri, Nov 21, 2014 at 1:26 PM, Andy Lutomirski wrote: > We currently pretend that IST context is like standard exception > context, but this is incorrect. IST entries from userspace are like > standard exceptions except that they use per-cpu stacks, so they are > atomic. IST entries from kerne

[PATCH v4 2/5] x86, traps: Track entry into and exit from IST context

2014-11-21 Thread Andy Lutomirski
We currently pretend that IST context is like standard exception context, but this is incorrect. IST entries from userspace are like standard exceptions except that they use per-cpu stacks, so they are atomic. IST entries from kernel space are like NMIs from RCU's perspective -- they are not quie