From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Seth Jennings <sjenning@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>, Jiri Slaby <jslaby@suse.cz>,
linux-kernel@vger.kernel.org
Subject: Re: Re: [RFC PATCH 0/2] kpatch: dynamic kernel patching
Date: Fri, 02 May 2014 10:30:57 +0900 [thread overview]
Message-ID: <5362F551.2030007@hitachi.com> (raw)
In-Reply-To: <20140501210601.GG2382@two.firstfloor.org>
(2014/05/02 6:06), Andi Kleen wrote:
>> When bar returns, would it skip foo and go straight back to foo's
>> caller? If so, then it should be safe to patch foo after it jumps to
>> bar.
>
> foo is no problem, you see it in the backtrace.
> But you don't see bar.
No, there is no "foo" in backtrace.
As Josh said, stop_machine() schedules highest priority tasks on
each running thread, as below.
buz:
...
call foo -> push buz on the stack
foo:
...
jmp bar
bar:
...
call schedule -> push bar on the stack
Thus, we'll not see foo on the stack. However, since the tail call
doesn't return to foo, we can treat it already finished. So, there
is no consistency problem on it. :)
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com
next prev parent reply other threads:[~2014-05-02 1:31 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-01 15:52 [RFC PATCH 0/2] kpatch: dynamic kernel patching Josh Poimboeuf
2014-05-01 15:52 ` [RFC PATCH 1/2] kpatch: add TAINT_KPATCH flag Josh Poimboeuf
2014-05-01 15:52 ` [RFC PATCH 2/2] kpatch: add kpatch core module Josh Poimboeuf
2014-05-01 20:45 ` [RFC PATCH 0/2] kpatch: dynamic kernel patching Andi Kleen
2014-05-01 21:01 ` Josh Poimboeuf
2014-05-01 21:06 ` Andi Kleen
2014-05-01 21:27 ` Josh Poimboeuf
2014-05-01 21:39 ` Josh Poimboeuf
2014-05-02 1:30 ` Masami Hiramatsu [this message]
2014-05-02 8:37 ` Jiri Kosina
2014-05-02 13:29 ` Josh Poimboeuf
2014-05-02 13:10 ` Jiri Kosina
2014-05-02 13:37 ` Josh Poimboeuf
2014-05-05 23:34 ` David Lang
2014-05-05 23:52 ` Jiri Kosina
2014-05-06 1:59 ` David Lang
2014-05-06 12:17 ` Josh Poimboeuf
2014-05-06 7:32 ` Ingo Molnar
2014-05-06 8:03 ` Jiri Kosina
2014-05-06 12:23 ` Josh Poimboeuf
2014-05-07 12:19 ` Ingo Molnar
2014-05-09 1:46 ` David Lang
2014-05-09 2:45 ` Steven Rostedt
2014-05-09 4:07 ` Masami Hiramatsu
2014-05-05 8:55 ` Ingo Molnar
2014-05-05 13:26 ` Josh Poimboeuf
2014-05-05 14:10 ` Frederic Weisbecker
2014-05-05 18:43 ` Ingo Molnar
2014-05-05 21:49 ` Frederic Weisbecker
2014-05-06 12:12 ` Josh Poimboeuf
2014-05-06 12:33 ` Steven Rostedt
2014-05-06 22:49 ` Masami Hiramatsu
2014-05-06 14:05 ` Frederic Weisbecker
2014-05-06 14:50 ` Josh Poimboeuf
2014-05-07 12:24 ` Ingo Molnar
2014-05-07 15:41 ` Josh Poimboeuf
2014-05-07 15:57 ` Ingo Molnar
2014-05-07 16:43 ` Josh Poimboeuf
2014-05-07 22:56 ` David Lang
2014-05-08 6:12 ` Ingo Molnar
2014-05-08 6:50 ` David Lang
2014-05-08 7:08 ` Ingo Molnar
2014-05-08 7:29 ` Masami Hiramatsu
2014-05-08 12:48 ` Josh Poimboeuf
2014-05-09 6:21 ` Masami Hiramatsu
2014-06-14 20:31 ` Pavel Machek
2014-06-15 6:57 ` Ingo Molnar
2014-05-06 11:45 ` Masami Hiramatsu
2014-05-06 12:26 ` Steven Rostedt
2014-05-06 22:33 ` Masami Hiramatsu
2014-05-16 16:27 ` Jiri Kosina
2014-05-16 17:14 ` Josh Poimboeuf
2014-05-20 9:37 ` Jiri Kosina
2014-05-20 12:59 ` Josh Poimboeuf
2014-05-16 18:09 ` Masami Hiramatsu
2014-05-17 22:46 ` Vojtech Pavlik
2014-05-16 18:55 ` Steven Rostedt
2014-05-16 22:32 ` Jiri Kosina
2014-05-17 0:27 ` Steven Rostedt
2014-05-17 7:10 ` Jiri Kosina
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