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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Namhyung Kim <namhyung@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
	Seth Jennings <sjenning@redhat.com>, Jiri Slaby <jslaby@suse.cz>
Subject: Re: [RFC][PATCH 0/3] ftrace: Add dynamically allocated trampolines
Date: Fri, 11 Jul 2014 11:26:34 +0900	[thread overview]
Message-ID: <53BF4B5A.3000302@hitachi.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1407102342050.8779@pobox.suse.cz>

(2014/07/11 6:44), Jiri Kosina wrote:
> On Thu, 10 Jul 2014, Josh Poimboeuf wrote:
> 
>> I did some testing with kpatch and I found one minor issue.  The dynamically
>> allocated trampoline seems to confuse dump_stack() somewhat.
>>
>> I added a dump_stack() call in my ftrace_ops callback function
>> (kpatch_ftrace_handler) which had a filter on meminfo_proc_show().
> 
> Interesting. Are you using dwarf2 unwinder for stack dumping by any 
> chance? It seems to get things right here. Will look into it more 
> tomorrow.

Hmm, can dwarf2 unwinder work on the trampoline method?
Since the trampoline just a copy of instructions which
will not have CFI(which is stored in dwarf section),
I guess it may not work...
Frame pointer (push bp and save sp to bp on the entry) can
work anyway.

Thank you,

-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com



  parent reply	other threads:[~2014-07-11  2:26 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-03 20:07 [RFC][PATCH 0/3] ftrace: Add dynamically allocated trampolines Steven Rostedt
2014-07-03 20:07 ` [RFC][PATCH 1/3] ftrace/x86: Add dynamic allocated trampoline for ftrace_ops Steven Rostedt
2014-07-04 13:32   ` Masami Hiramatsu
2014-07-04 14:25     ` Steven Rostedt
2014-07-14  2:34   ` Masami Hiramatsu
2014-07-03 20:07 ` [RFC][PATCH 2/3] ftrace/x86: Show trampoline call function in enabled_functions Steven Rostedt
2014-07-03 20:07 ` [RFC][PATCH 3/3] ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines Steven Rostedt
2014-07-03 20:32 ` [RFC][PATCH 0/3] ftrace: Add dynamically " Steven Rostedt
2014-07-04 13:20 ` Masami Hiramatsu
2014-07-04 14:21   ` Steven Rostedt
2014-07-07 13:22     ` Jiri Kosina
2014-07-08 14:24       ` Steven Rostedt
2014-07-07 13:58 ` Jiri Kosina
2014-07-10 21:36 ` Josh Poimboeuf
2014-07-10 21:44   ` Jiri Kosina
2014-07-10 22:01     ` Josh Poimboeuf
2014-07-11  2:26     ` Masami Hiramatsu [this message]
2014-07-11 13:24       ` Jiri Kosina
2014-07-11 14:29         ` Josh Poimboeuf
2014-07-14  1:35           ` Masami Hiramatsu
2014-07-14  7:16             ` Namhyung Kim
2014-07-14  8:18               ` Masami Hiramatsu
2014-07-14 14:18                 ` Namhyung Kim
2014-07-15  1:20                   ` Masami Hiramatsu
2014-07-22 16:47 ` Oleg Nesterov
2014-07-22 19:02   ` Steven Rostedt
2014-07-23 12:08     ` Oleg Nesterov
2014-07-23 15:48       ` Steven Rostedt
2014-07-23 17:05         ` Oleg Nesterov
2014-07-23 17:20           ` Steven Rostedt

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