From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
"Frank Ch. Eigler" <fche@redhat.com>
Subject: [PATCH 14/19] kprobes: Inverse taking of module_mutex with kprobe_mutex
Date: Fri, 20 Jul 2012 22:19:57 -0400 [thread overview]
Message-ID: <20120721022110.650726104@goodmis.org> (raw)
In-Reply-To: 20120721021943.274162381@goodmis.org
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From: Steven Rostedt <srostedt@redhat.com>
Currently module_mutex is taken before kprobe_mutex, but this
can cause issues when we have kprobes register ftrace, as the ftrace
mutex is taken before enabling a tracepoint, which currently takes
the module mutex.
If module_mutex is taken before kprobe_mutex, then we can not
have kprobes use the ftrace infrastructure.
There seems to be no reason that the kprobe_mutex can't be taken
before the module_mutex. Running lockdep shows that it is safe
among the kernels I've run.
Link: http://lkml.kernel.org/r/20120605102814.27845.21047.stgit@localhost.localdomain
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/kprobes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c62b854..7a8a122 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -561,9 +561,9 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
{
LIST_HEAD(free_list);
+ mutex_lock(&kprobe_mutex);
/* Lock modules while optimizing kprobes */
mutex_lock(&module_mutex);
- mutex_lock(&kprobe_mutex);
/*
* Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
@@ -586,8 +586,8 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
/* Step 4: Free cleaned kprobes after quiesence period */
do_free_cleaned_kprobes(&free_list);
- mutex_unlock(&kprobe_mutex);
mutex_unlock(&module_mutex);
+ mutex_unlock(&kprobe_mutex);
/* Step 5: Kick optimizer again if needed */
if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
--
1.7.10.4
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next prev parent reply other threads:[~2012-07-21 2:22 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-21 2:19 [PATCH 00/19] [GIT PULL][v3.6] ftrace: Allow kprobes to work with ftace Steven Rostedt
2012-07-21 2:19 ` [PATCH 01/19] ftrace: Pass ftrace_ops as third parameter to function trace callback Steven Rostedt
2012-07-21 2:19 ` [PATCH 02/19] ftrace: Consolidate arch dependent functions with list function Steven Rostedt
2012-07-21 2:19 ` [PATCH 03/19] ftrace: Return pt_regs to function trace callback Steven Rostedt
2012-07-21 2:19 ` [PATCH 04/19] ftrace/x86_32: Push ftrace_ops in as 3rd parameter to function tracer Steven Rostedt
2012-07-21 2:19 ` [PATCH 05/19] ftrace/x86: Add separate function to save regs Steven Rostedt
2012-07-21 2:19 ` [PATCH 06/19] ftrace/x86: Add save_regs for i386 function calls Steven Rostedt
2012-07-21 2:19 ` [PATCH 07/19] ftrace/x86_32: Simplify parameter setup for ftrace_regs_caller Steven Rostedt
2012-07-23 4:06 ` Masami Hiramatsu
2012-07-21 2:19 ` [PATCH 08/19] ftrace/x86: Remove function_trace_stop check from graph caller Steven Rostedt
2012-07-21 2:19 ` [PATCH 09/19] ftrace: Add default recursion protection for function tracing Steven Rostedt
2012-07-21 2:19 ` [PATCH 10/19] ftrace: Only compile ftrace selftest if selftests are enabled Steven Rostedt
2012-07-21 2:19 ` [PATCH 11/19] ftrace: Add selftest to test function trace recursion protection Steven Rostedt
2012-07-21 2:19 ` [PATCH 12/19] ftrace: Add selftest to test function save-regs support Steven Rostedt
2012-07-21 2:19 ` [PATCH 13/19] ftrace: add ftrace_set_filter_ip() for address based filter Steven Rostedt
2012-07-21 2:19 ` Steven Rostedt [this message]
2012-07-21 2:19 ` [PATCH 15/19] kprobes: cleanup to separate probe-able check Steven Rostedt
2012-07-21 2:19 ` [PATCH 16/19] kprobes: Move locks into appropriate functions Steven Rostedt
2012-07-21 2:20 ` [PATCH 17/19] ftrace: Make ftrace_location() a nop on !DYNAMIC_FTRACE Steven Rostedt
2012-07-21 2:20 ` [PATCH 18/19] kprobes: introduce ftrace based optimization Steven Rostedt
2012-07-21 2:20 ` [PATCH 19/19] kprobes/x86: ftrace based optimization for x86 Steven Rostedt
2012-07-30 15:51 ` [PATCH 00/19] [GIT PULL][v3.6] ftrace: Allow kprobes to work with ftace Steven Rostedt
2012-07-31 14:37 ` [GIT PULL][v3.7] (was: Re: [PATCH 00/19] [GIT PULL][v3.6]) " Steven Rostedt
2012-07-31 15:12 ` [PATCH 00/19] [GIT PULL][v3.6] " Ingo Molnar
2012-08-07 13:23 ` Steven Rostedt
2012-08-21 9:26 ` Ingo Molnar
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