linux-kernel - [PATCH v2 1/2] Replace if statement with WARN_ON_ONCE() in cmci

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Date:	Fri, 19 Oct 2012 13:45:27 +0800
From:	Tang Chen <tangchen@...fujitsu.com>
To:	stable@...r.kernel.org, tony.luck@...el.com, bp@...64.org,
	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	miaox@...fujitsu.com, laijs@...fujitsu.com, wency@...fujitsu.com,
	x86@...nel.org, linux-edac@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] Replace if statement with WARN_ON_ONCE() in cmci_rediscover().

cmci_rediscover() is only called by the CPU_POST_DEAD event handler,
which means the corresponding cpu has already dead. As a result, it
won't be accessed in the for_each_online_cpu loop.
So, we could change the if(cpu == dying) statement into a WARN_ON_ONCE().

Signed-off-by: Tang Chen <tangchen@...fujitsu.com>
---
 arch/x86/kernel/cpu/mcheck/mce_intel.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c
index 38e49bc..481d152 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_intel.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c
@@ -180,8 +180,8 @@ void cmci_rediscover(int dying)
 	cpumask_copy(old, &current->cpus_allowed);
 
 	for_each_online_cpu(cpu) {
-		if (cpu == dying)
-			continue;
+		WARN_ON_ONCE(cpu == dying);
+
 		if (set_cpus_allowed_ptr(current, cpumask_of(cpu)))
 			continue;
 		/* Recheck banks in case CPUs don't all have the same */
-- 
1.7.1

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