From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
Jessica Yu <jeyu@redhat.com>, Miroslav Benes <mbenes@suse.cz>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
live-patching@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>,
linuxppc-dev@lists.ozlabs.org,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
Vojtech Pavlik <vojtech@suse.com>, Jiri Slaby <jslaby@suse.cz>,
Petr Mladek <pmladek@suse.com>,
Chris J Arges <chris.j.arges@canonical.com>,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking
Date: Fri, 29 Apr 2016 17:57:57 -0500 [thread overview]
Message-ID: <20160429225757.n7mjjysomnf5ns53@treble> (raw)
In-Reply-To: <alpine.LNX.2.00.1604300007070.27368@cbobk.fhfr.pm>
On Sat, Apr 30, 2016 at 12:11:45AM +0200, Jiri Kosina wrote:
> On Fri, 29 Apr 2016, Andy Lutomirski wrote:
> > > NMI, MCE and interrupts aren't a problem because they have dedicated
> > > stacks, which are easy to detect. If the tasks' stack is on an
> > > exception stack or an irq stack, we consider it unreliable.
> >
> > Only on x86_64.
>
> Well, MCEs are more or less x86-specific as well. But otherwise good
> point, thanks Andy.
>
> So, how does stack layout generally look like in case when NMI is actually
> running on proper kernel stack? I thought it's guaranteed to contain
> pt_regs anyway in all cases. Is that not guaranteed to be the case?
If the NMI were using the normal kernel stack and it interrupted kernel
space, pt_regs would be placed in the "middle" of the stack rather than
the bottom, and there's currently no way to detect that.
However, NMIs don't sleep, and we only consider sleeping tasks for stack
reliability, so it wouldn't be an issue anyway.
--
Josh
next prev parent reply other threads:[~2016-04-29 22:58 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-28 20:44 [RFC PATCH v2 00/18] livepatch: hybrid consistency model Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 01/18] x86/asm/head: clean up initial stack variable Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 02/18] x86/asm/head: use a common function for starting CPUs Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 03/18] x86/asm/head: standardize the bottom of the stack for idle tasks Josh Poimboeuf
2016-04-29 18:46 ` Brian Gerst
2016-04-29 20:28 ` Josh Poimboeuf
2016-04-29 19:39 ` Andy Lutomirski
2016-04-29 20:50 ` Josh Poimboeuf
2016-04-29 21:38 ` Andy Lutomirski
2016-04-29 23:27 ` Josh Poimboeuf
2016-04-30 0:10 ` Andy Lutomirski
2016-04-28 20:44 ` [RFC PATCH v2 04/18] x86: move _stext marker before head code Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking Josh Poimboeuf
2016-04-29 18:06 ` Andy Lutomirski
2016-04-29 20:11 ` Josh Poimboeuf
2016-04-29 20:19 ` Andy Lutomirski
2016-04-29 20:27 ` Josh Poimboeuf
2016-04-29 20:32 ` Andy Lutomirski
2016-04-29 21:25 ` Josh Poimboeuf
2016-04-29 21:37 ` Andy Lutomirski
2016-04-29 22:11 ` Jiri Kosina
2016-04-29 22:57 ` Josh Poimboeuf [this message]
2016-04-30 0:09 ` Andy Lutomirski
2016-04-29 22:41 ` Josh Poimboeuf
2016-04-30 0:08 ` Andy Lutomirski
2016-05-02 13:52 ` Josh Poimboeuf
2016-05-02 15:52 ` Andy Lutomirski
2016-05-02 17:31 ` Josh Poimboeuf
2016-05-02 18:12 ` Andy Lutomirski
2016-05-02 18:34 ` Ingo Molnar
2016-05-02 19:44 ` Josh Poimboeuf
2016-05-02 19:54 ` Jiri Kosina
2016-05-02 20:00 ` Jiri Kosina
2016-05-03 0:39 ` Andy Lutomirski
2016-05-04 15:16 ` David Laight
2016-05-19 23:15 ` Josh Poimboeuf
2016-05-19 23:39 ` Andy Lutomirski
2016-05-20 14:05 ` Josh Poimboeuf
2016-05-20 15:41 ` Andy Lutomirski
2016-05-20 16:41 ` Josh Poimboeuf
2016-05-20 16:59 ` Andy Lutomirski
2016-05-20 17:49 ` Josh Poimboeuf
2016-05-23 23:02 ` Jiri Kosina
2016-05-24 1:42 ` Andy Lutomirski
2016-05-23 21:34 ` Andy Lutomirski
2016-05-24 2:28 ` Josh Poimboeuf
2016-05-24 3:52 ` Andy Lutomirski
2016-06-22 16:30 ` Josh Poimboeuf
2016-06-22 17:59 ` Andy Lutomirski
2016-06-22 18:22 ` Josh Poimboeuf
2016-06-22 18:26 ` Andy Lutomirski
2016-06-22 18:40 ` Josh Poimboeuf
2016-06-22 19:17 ` Andy Lutomirski
2016-06-23 16:19 ` Josh Poimboeuf
2016-06-23 16:35 ` Andy Lutomirski
2016-06-23 18:31 ` Josh Poimboeuf
2016-06-23 20:40 ` Josh Poimboeuf
2016-06-23 22:00 ` Andy Lutomirski
2016-06-23 0:09 ` Andy Lutomirski
2016-06-23 15:55 ` Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 06/18] x86: dump_trace() error handling Josh Poimboeuf
2016-04-29 13:45 ` Minfei Huang
2016-04-29 14:00 ` Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 07/18] stacktrace/x86: function for detecting reliable stack traces Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 08/18] livepatch: temporary stubs for klp_patch_pending() and klp_patch_task() Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 09/18] livepatch/x86: add TIF_PATCH_PENDING thread flag Josh Poimboeuf
2016-04-29 18:08 ` Andy Lutomirski
2016-04-29 20:18 ` Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 10/18] livepatch/powerpc: " Josh Poimboeuf
2016-05-03 9:07 ` Petr Mladek
2016-05-03 12:06 ` Miroslav Benes
2016-04-28 20:44 ` [RFC PATCH v2 11/18] livepatch/s390: reorganize TIF thread flag bits Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 12/18] livepatch/s390: add TIF_PATCH_PENDING thread flag Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 13/18] livepatch: separate enabled and patched states Josh Poimboeuf
2016-05-03 9:30 ` Petr Mladek
2016-05-03 13:48 ` Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 14/18] livepatch: remove unnecessary object loaded check Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 15/18] livepatch: move patching functions into patch.c Josh Poimboeuf
2016-05-03 9:39 ` Petr Mladek
2016-04-28 20:44 ` [RFC PATCH v2 16/18] livepatch: store function sizes Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 17/18] livepatch: change to a per-task consistency model Josh Poimboeuf
2016-05-04 8:42 ` Petr Mladek
2016-05-04 15:51 ` Josh Poimboeuf
2016-05-05 9:41 ` Miroslav Benes
2016-05-05 13:06 ` Petr Mladek
2016-05-04 12:39 ` barriers: was: " Petr Mladek
2016-05-04 13:53 ` Peter Zijlstra
2016-05-04 16:51 ` Josh Poimboeuf
2016-05-04 14:12 ` Petr Mladek
2016-05-04 17:25 ` Josh Poimboeuf
2016-05-05 11:21 ` Petr Mladek
2016-05-09 15:42 ` Miroslav Benes
2016-05-04 17:02 ` Josh Poimboeuf
2016-05-05 10:21 ` Petr Mladek
2016-05-04 14:48 ` klp_task_patch: " Petr Mladek
2016-05-04 14:56 ` Jiri Kosina
2016-05-04 17:57 ` Josh Poimboeuf
2016-05-05 11:57 ` Petr Mladek
2016-05-06 12:38 ` Josh Poimboeuf
2016-05-09 12:23 ` Petr Mladek
2016-05-16 18:12 ` Josh Poimboeuf
2016-05-18 13:12 ` Petr Mladek
2016-05-06 11:33 ` Petr Mladek
2016-05-06 12:44 ` Josh Poimboeuf
2016-05-09 9:41 ` Miroslav Benes
2016-05-16 17:27 ` Josh Poimboeuf
2016-05-10 11:39 ` Miroslav Benes
2016-05-17 22:53 ` Jessica Yu
2016-05-18 8:16 ` Jiri Kosina
2016-05-18 16:51 ` Josh Poimboeuf
2016-05-18 20:22 ` Jiri Kosina
2016-05-23 9:42 ` David Laight
2016-05-23 18:44 ` Jiri Kosina
2016-05-24 15:06 ` David Laight
2016-05-24 22:45 ` Jiri Kosina
2016-06-06 13:54 ` [RFC PATCH v2 17/18] " Petr Mladek
2016-06-06 14:29 ` Josh Poimboeuf
2016-04-28 20:44 ` [RFC PATCH v2 18/18] livepatch: add /proc/<pid>/patch_state Josh Poimboeuf
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