From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Jiri Kosina <jkosina@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>,
Jiri Slaby <jslaby@suse.cz>, Ingo Molnar <mingo@redhat.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Seth Jennings <sjenning@redhat.com>,
Vojtech Pavlik <vojtech@suse.cz>
Subject: Re: [RFC PATCH 6/9] livepatch: create per-task consistency model
Date: Thu, 12 Feb 2015 09:24:05 -0600 [thread overview]
Message-ID: <20150212152405.GE18578@treble.redhat.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1502121501330.20672@pobox.suse.cz>
On Thu, Feb 12, 2015 at 03:08:38PM +0100, Jiri Kosina wrote:
> On Thu, 12 Feb 2015, Peter Zijlstra wrote:
> I personally am not a big fan of the task_rq_lock() public exposure
> either. What might be generally useful though (not only for livepatching)
> would be an API that would allow for "safe" stack dump (where "safe" means
> that guarantee, that it wouldn't be interferred by process waking up in
> the middle of dumping, would be provided).
In general, I think a safe stack dump is needed. A lot of the stack
dumping in the kernel seems dangerous. For example, it looks like doing
a `cat /proc/pid/stack` while the process is writing the stack could
easily go off into the weeds.
But I don't see how it would help the livepatch case. What happens if
the process starts running in the to-be-patched function after we call
the "safe" dump_stack() but before switching it to the new universe?
--
Josh
next prev parent reply other threads:[~2015-02-12 15:24 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-09 17:31 [RFC PATCH 0/9] livepatch: consistency model Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 1/9] livepatch: simplify disable error path Josh Poimboeuf
2015-02-13 12:25 ` Miroslav Benes
2015-02-18 17:03 ` Petr Mladek
2015-02-18 20:07 ` Jiri Kosina
2015-02-09 17:31 ` [RFC PATCH 2/9] livepatch: separate enabled and patched states Josh Poimboeuf
2015-02-10 16:44 ` Jiri Slaby
2015-02-10 17:21 ` Josh Poimboeuf
2015-02-13 12:57 ` Miroslav Benes
2015-02-13 14:39 ` Josh Poimboeuf
2015-02-13 14:46 ` Miroslav Benes
2015-02-09 17:31 ` [RFC PATCH 3/9] livepatch: move patching functions into patch.c Josh Poimboeuf
2015-02-10 18:27 ` Jiri Slaby
2015-02-10 18:50 ` Josh Poimboeuf
2015-02-13 14:28 ` Miroslav Benes
2015-02-13 15:09 ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 4/9] livepatch: get function sizes Josh Poimboeuf
2015-02-10 18:30 ` Jiri Slaby
2015-02-10 18:53 ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 5/9] sched: move task rq locking functions to sched.h Josh Poimboeuf
2015-02-10 10:48 ` Masami Hiramatsu
2015-02-10 14:54 ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 6/9] livepatch: create per-task consistency model Josh Poimboeuf
2015-02-10 10:58 ` Masami Hiramatsu
2015-02-10 14:59 ` Josh Poimboeuf
2015-02-10 15:59 ` Miroslav Benes
2015-02-10 16:56 ` Josh Poimboeuf
2015-02-11 16:28 ` Miroslav Benes
2015-02-11 20:23 ` Josh Poimboeuf
2015-02-10 19:27 ` Seth Jennings
2015-02-10 19:32 ` Josh Poimboeuf
2015-02-11 10:21 ` Miroslav Benes
2015-02-11 20:19 ` Josh Poimboeuf
2015-02-12 10:45 ` Miroslav Benes
2015-02-12 3:21 ` Josh Poimboeuf
2015-02-12 11:56 ` Peter Zijlstra
2015-02-12 12:25 ` Jiri Kosina
2015-02-12 12:36 ` Peter Zijlstra
2015-02-12 12:39 ` Jiri Kosina
2015-02-12 12:39 ` Peter Zijlstra
2015-02-12 12:42 ` Jiri Kosina
2015-02-12 13:01 ` Josh Poimboeuf
2015-02-12 12:51 ` Josh Poimboeuf
2015-02-12 13:08 ` Peter Zijlstra
2015-02-12 13:16 ` Jiri Kosina
2015-02-12 14:20 ` Josh Poimboeuf
2015-02-12 14:27 ` Jiri Kosina
2015-02-12 13:16 ` Jiri Slaby
2015-02-12 13:35 ` Peter Zijlstra
2015-02-12 14:08 ` Jiri Kosina
2015-02-12 15:24 ` Josh Poimboeuf [this message]
2015-02-12 14:20 ` Jiri Slaby
2015-02-12 14:32 ` Jiri Kosina
2015-02-18 20:17 ` Ingo Molnar
2015-02-18 20:44 ` Vojtech Pavlik
2015-02-19 9:52 ` Peter Zijlstra
2015-02-19 10:11 ` Vojtech Pavlik
2015-02-19 10:51 ` Peter Zijlstra
2015-02-12 13:26 ` Jiri Slaby
2015-02-12 15:48 ` Josh Poimboeuf
2015-02-14 11:40 ` Jiri Slaby
2015-02-17 14:59 ` Josh Poimboeuf
2015-02-16 14:19 ` Miroslav Benes
2015-02-17 15:10 ` Josh Poimboeuf
2015-02-17 15:48 ` Miroslav Benes
2015-02-17 16:01 ` Josh Poimboeuf
2015-02-18 12:42 ` Miroslav Benes
2015-02-18 13:15 ` Josh Poimboeuf
2015-02-18 13:42 ` Miroslav Benes
2015-02-09 17:31 ` [RFC PATCH 7/9] proc: add /proc/<pid>/universe to show livepatch status Josh Poimboeuf
2015-02-10 18:47 ` Jiri Slaby
2015-02-10 18:57 ` Josh Poimboeuf
2015-02-09 17:31 ` [RFC PATCH 8/9] livepatch: allow patch modules to be removed Josh Poimboeuf
2015-02-10 19:02 ` Jiri Slaby
2015-02-10 19:57 ` Josh Poimboeuf
2015-02-11 10:55 ` Jiri Slaby
2015-02-11 18:39 ` Josh Poimboeuf
2015-02-12 15:22 ` Miroslav Benes
2015-02-13 12:44 ` Josh Poimboeuf
2015-02-13 16:04 ` Josh Poimboeuf
2015-02-13 16:17 ` Miroslav Benes
2015-02-13 20:49 ` Josh Poimboeuf
2015-02-16 16:06 ` Miroslav Benes
2015-02-17 15:55 ` Josh Poimboeuf
2015-02-17 16:38 ` Miroslav Benes
2015-02-09 17:31 ` [RFC PATCH 9/9] livepatch: update task universe when exiting kernel Josh Poimboeuf
2015-02-16 10:16 ` Jiri Slaby
2015-02-17 14:58 ` Josh Poimboeuf
2015-02-09 23:15 ` [RFC PATCH 0/9] livepatch: consistency model Jiri Kosina
2015-02-10 3:05 ` Josh Poimboeuf
2015-02-10 7:21 ` Jiri Kosina
2015-02-10 8:57 ` Jiri Kosina
2015-02-10 14:43 ` Josh Poimboeuf
2015-02-10 11:16 ` Masami Hiramatsu
2015-02-10 15:59 ` Josh Poimboeuf
2015-02-10 17:29 ` Josh Poimboeuf
2015-02-13 10:14 ` Jiri Kosina
2015-02-13 14:19 ` Josh Poimboeuf
2015-02-13 14:22 ` Jiri Kosina
2015-02-13 14:40 ` Miroslav Benes
2015-02-13 14:55 ` Josh Poimboeuf
2015-02-13 14:41 ` Josh Poimboeuf
2015-02-24 11:27 ` Masami Hiramatsu
2015-03-10 16:23 ` Josh Poimboeuf
2015-03-10 21:02 ` Jiri Kosina
2015-03-10 21:30 ` Josh Poimboeuf
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