From: Masami Hiramatsu <mhiramat@redhat.com>
To: Tim Abbott <tabbott@MIT.EDU>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
Anders Kaseorg <andersk@MIT.EDU>, Ingo Molnar <mingo@elte.hu>,
Rusty Russell <rusty@rustcorp.com.au>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Jeffrey B Arnold <jbarnold@MIT.EDU>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Subject: Re: [PATCH 1/5] ftrace: use module notifier for function tracer
Date: Thu, 23 Apr 2009 23:11:38 -0400 [thread overview]
Message-ID: <49F12DEA.6070404@redhat.com> (raw)
In-Reply-To: <alpine.DEB.1.10.0904231612180.28329@vinegar-pot.mit.edu>
Tim Abbott wrote:
> The reason that we want to export text_mutex is that it can be useful for
> the Ksplice core (still kernel/ksplice.c) to be built as a module. This
> is desirable when a different version of the kernel/ksplice.c code is
> needed in order to apply a particular update (e.g. because there was a bug
> in Ksplice).
Ah, OK. Certainly, Ksplice can't patch itself. It might be a good reason for
exporting text_mutex.
> I agree that great care should be taken when writing code that patches the
> kernel's text. However, I don't think failing to export text_mutex to GPL
> modules helps ensure that. In particular, not exporting text_mutex
> doesn't prevent modules from patching the kernel text. It just prevents
> any modules that do so from grabbing the appropriate lock.
What I'm concerned about exporting locking staffs is that may cause
a dead lock. However, we've already exported module_mutex.
I don't think that exporting text_mutex is more considerable than that. :-)
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
next prev parent reply other threads:[~2009-04-24 3:13 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-16 2:18 [PATCH 0/5] [GIT PULL] updates for tip Steven Rostedt
2009-04-16 2:18 ` [PATCH 1/5] ftrace: use module notifier for function tracer Steven Rostedt
2009-04-16 15:36 ` Frederic Weisbecker
2009-04-16 15:53 ` Steven Rostedt
2009-04-17 11:44 ` Steven Rostedt
2009-04-19 11:25 ` Rusty Russell
2009-04-20 13:57 ` Steven Rostedt
2009-04-21 5:15 ` Rusty Russell
2009-04-21 13:13 ` Steven Rostedt
2009-04-21 13:58 ` Ingo Molnar
2009-04-21 17:51 ` Tim Abbott
2009-04-21 18:17 ` Steven Rostedt
2009-04-21 18:47 ` Tim Abbott
2009-04-22 9:16 ` Ingo Molnar
2009-04-22 22:20 ` Tim Abbott
2009-04-22 22:57 ` Masami Hiramatsu
2009-04-23 19:40 ` Anders Kaseorg
2009-04-23 19:57 ` Mathieu Desnoyers
2009-04-23 22:31 ` Tim Abbott
2009-04-24 3:11 ` Masami Hiramatsu [this message]
2009-04-23 20:06 ` Masami Hiramatsu
2009-04-16 2:18 ` [PATCH 2/5] tracing/events: add startup tests for events Steven Rostedt
2009-04-16 8:39 ` [PATCH] tracing: add #include <linux/delay.h> to fix build failure in test_work() Ingo Molnar
2009-04-16 14:08 ` Steven Rostedt
2009-04-17 0:30 ` Ingo Molnar
2009-04-16 15:41 ` [PATCH 2/5] tracing/events: add startup tests for events Frederic Weisbecker
2009-04-16 15:51 ` Steven Rostedt
2009-04-16 16:02 ` Frederic Weisbecker
2009-04-16 2:18 ` [PATCH 3/5] tracing/events: add rcu locking around trace event prints Steven Rostedt
2009-04-17 14:08 ` Steven Rostedt
2009-04-17 15:20 ` Jeremy Fitzhardinge
2009-04-17 15:42 ` Steven Rostedt
2009-04-17 23:53 ` Jeremy Fitzhardinge
2009-04-17 16:18 ` Theodore Tso
2009-04-17 16:32 ` Jeremy Fitzhardinge
2009-04-17 16:41 ` Steven Rostedt
2009-05-07 2:10 ` Steven Rostedt
2009-05-07 11:32 ` Ingo Molnar
2009-05-07 13:10 ` Steven Rostedt
2009-04-16 2:18 ` [PATCH 4/5] tracing/events/ring-buffer: expose format of ring buffer headers to users Steven Rostedt
2009-04-16 2:18 ` [PATCH 5/5] tracing: add saved_cmdlines file to show cached task comms Steven Rostedt
2009-04-16 15:54 ` Frederic Weisbecker
2009-04-16 15:58 ` Steven Rostedt
2009-04-16 16:05 ` Frederic Weisbecker
2009-04-16 9:51 ` [PATCH 0/5] [GIT PULL] updates for tip Ingo Molnar
2009-04-16 9:53 ` Ingo Molnar
2009-04-16 13:52 ` Steven Rostedt
2009-04-16 16:12 ` Ingo Molnar
2009-04-16 16:22 ` Steven Rostedt
2009-04-17 0:29 ` Ingo Molnar
2009-04-16 16:30 ` Ingo Molnar
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