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From: Jiri Kosina <jkosina@suse.cz>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@kernel.org>, Andi Kleen <ak@linux.intel.com>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	Sandeepa Prabhu <sandeepa.prabhu@linaro.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	x86@kernel.org, lkml <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@redhat.com>,
	systemtap@sourceware.org, "H. Peter Anvin" <hpa@zytor.com>,
	Sasha Levin <sasha.levin@oracle.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Seiji Aguchi <seiji.aguchi@hds.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH -tip v4 6/6] [RFC] kprobes/x86: Call exception handlers directly from do_int3/do_debug
Date: Thu, 12 Dec 2013 10:59:34 +0100 (CET)	[thread overview]
Message-ID: <alpine.LNX.2.00.1312121058220.1413@pobox.suse.cz> (raw)
In-Reply-To: <52A93E3A.9080600@hitachi.com>

On Thu, 12 Dec 2013, Masami Hiramatsu wrote:

> > Yeah, it's broken. Obviously, if you happen to trigger int3 before the 
> > notifier has been registered, it'd cause int3 exception to be unhandled. 
> > See
> > 
> > 	commit 17f41571bb2c4a398785452ac2718a6c5d77180e
> > 	Author: Jiri Kosina <jkosina@suse.cz>
> > 	Date:   Tue Jul 23 10:09:28 2013 +0200
> > 
> > 	    kprobes/x86: Call out into INT3 handler directly instead of using notifier
> > 
> > for one such issue that happened with jump labels.
> > 
> >> Hmm, if there's no users of the int3 notifier, should we just remove it?
> > 
> > Hmm, there are still uprobes, right?
> 
> Right, uprobes still use it, however, since it only handles user-space
> breakpoint, there is no problem.

Agreed. But therefore the notifier can't just be removed, unless uprobes 
are converted to direct call as well (but I don't think that'd be 
beneficial, notifier is sufficient in this case).

-- 
Jiri Kosina
SUSE Labs

  reply	other threads:[~2013-12-12  9:59 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-04  1:28 [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs Masami Hiramatsu
2013-12-04  1:28 ` [PATCH -tip v4 1/6] kprobes: Prohibit probing on .entry.text code Masami Hiramatsu
2013-12-04  1:28 ` [PATCH -tip v4 2/6] kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist Masami Hiramatsu
2013-12-04  1:28 ` [PATCH -tip v4 3/6] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* Masami Hiramatsu
2013-12-04  1:28 ` [PATCH -tip v4 4/6] [BUGFIX] x86: Prohibit probing on native_set_debugreg Masami Hiramatsu
2013-12-04  1:28 ` [PATCH -tip v4 5/6] [BUGFIX] x86: Prohibit probing on thunk functions and restore Masami Hiramatsu
2013-12-04  1:28 ` [PATCH -tip v4 6/6] [RFC] kprobes/x86: Call exception handlers directly from do_int3/do_debug Masami Hiramatsu
2013-12-04  2:39   ` Steven Rostedt
2013-12-11 13:31     ` Jiri Kosina
2013-12-12  4:40       ` Masami Hiramatsu
2013-12-12  9:59         ` Jiri Kosina [this message]
2013-12-12 10:31           ` Masami Hiramatsu
2013-12-04  2:54 ` [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs Sandeepa Prabhu
2013-12-04  7:39   ` Masami Hiramatsu
2013-12-04  8:46     ` Sandeepa Prabhu
2013-12-04 23:32       ` Masami Hiramatsu
2013-12-04  8:45 ` Ingo Molnar
2013-12-04 23:27   ` Masami Hiramatsu
2013-12-05 10:21     ` Ingo Molnar
2013-12-06  2:34       ` Masami Hiramatsu
2013-12-10 15:28         ` Ingo Molnar
2013-12-11  2:12           ` Masami Hiramatsu
2013-12-11 13:34             ` Ingo Molnar
2013-12-12  6:02               ` Masami Hiramatsu
2013-12-12 14:03                 ` Ingo Molnar
2013-12-12 20:42                   ` Josh Stone
2013-12-13  5:34                   ` Masami Hiramatsu
2013-12-13  6:06                     ` Masami Hiramatsu
2013-12-16 10:53                     ` Masami Hiramatsu
2013-12-05 13:08     ` Sandeepa Prabhu
2013-12-06  6:23       ` Masami Hiramatsu
2013-12-06  6:54         ` Sandeepa Prabhu
2013-12-06 23:25           ` Masami Hiramatsu
2013-12-05 14:49     ` Frank Ch. Eigler
2013-12-06  6:12       ` Masami Hiramatsu
2013-12-06 19:07         ` Frank Ch. Eigler
2013-12-06 23:19           ` Masami Hiramatsu
2013-12-07  1:32             ` Frank Ch. Eigler
2013-12-07  2:34               ` Masami Hiramatsu

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