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From: tip-bot for Ming Lei <tom.leiming@gmail.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com,
	torvalds@linux-foundation.org, a.p.zijlstra@chello.nl,
	akpm@linux-foundation.org, tglx@linutronix.de,
	yong.zhang0@gmail.com, tom.leiming@gmail.com, mingo@elte.hu
Subject: [tip:core/locking] init/main.c: Execute lockdep_init() as early as possible
Date: Tue, 6 Dec 2011 01:40:28 -0800	[thread overview]
Message-ID: <tip-73839c5b2eacc15cb0aa79c69b285fc659fa8851@git.kernel.org> (raw)
In-Reply-To: <1321508072-23853-1-git-send-email-tom.leiming@gmail.com>

Commit-ID:  73839c5b2eacc15cb0aa79c69b285fc659fa8851
Gitweb:     http://git.kernel.org/tip/73839c5b2eacc15cb0aa79c69b285fc659fa8851
Author:     Ming Lei <tom.leiming@gmail.com>
AuthorDate: Thu, 17 Nov 2011 13:34:31 +0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 6 Dec 2011 08:16:53 +0100

init/main.c: Execute lockdep_init() as early as possible

This patch fixes a lockdep warning on ARM platforms:

  [    0.000000] WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?
  [    0.000000] Call stack leading to lockdep invocation was:
  [    0.000000]  [<c00164bc>] save_stack_trace_tsk+0x0/0x90
  [    0.000000]  [<ffffffff>] 0xffffffff

The warning is caused by printk inside smp_setup_processor_id().

It is safe to do this because lockdep_init() doesn't depend on
smp_setup_processor_id(), so improve things that printk can be
called as early as possible without lockdep complaint.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1321508072-23853-1-git-send-email-tom.leiming@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 init/main.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/init/main.c b/init/main.c
index 217ed23..2c76efb 100644
--- a/init/main.c
+++ b/init/main.c
@@ -469,13 +469,12 @@ asmlinkage void __init start_kernel(void)
 	char * command_line;
 	extern const struct kernel_param __start___param[], __stop___param[];
 
-	smp_setup_processor_id();
-
 	/*
 	 * Need to run as early as possible, to initialize the
 	 * lockdep hash:
 	 */
 	lockdep_init();
+	smp_setup_processor_id();
 	debug_objects_early_init();
 
 	/*

      parent reply	other threads:[~2011-12-06  9:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-17  5:34 [PATCH 1/2] init/main.c: execute lockdep_init as early as possible tom.leiming
2011-11-17  5:34 ` [PATCH 2/2] lockdep: print lock name for lockdep_init_error tom.leiming
2011-11-17  6:02   ` Yong Zhang
2011-11-17  8:01     ` Ming Lei
2011-11-17  8:44       ` Yong Zhang
2011-11-17  9:01         ` Peter Zijlstra
2011-11-17 21:50   ` Ryan Mallon
2011-12-06  9:41   ` [tip:core/locking] lockdep: Print lock name in lockdep_init_error() tip-bot for Ming Lei
2011-11-17  5:59 ` [PATCH 1/2] init/main.c: execute lockdep_init as early as possible Yong Zhang
2011-12-06  9:40 ` tip-bot for Ming Lei [this message]

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