linux-kernel - [PATCH 2/5] x86: mce: Serialize mce injection

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Message-Id: <1342720781-4729-3-git-send-email-gong.chen@linux.intel.com>
Date:	Thu, 19 Jul 2012 13:59:38 -0400
From:	Chen Gong <gong.chen@...ux.intel.com>
To:	tglx@...utronix.de
Cc:	tony.luck@...el.com, bp@...64.org, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/5] x86: mce: Serialize mce injection

From: Thomas Gleixner <tglx@...utronix.de>

raise_mce() fiddles with global state, but lacks any kind of
serialization.

Add a mutex around the raise_mce() call, so concurrent writers do not
stomp on each other toes.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/cpu/mcheck/mce-inject.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/cpu/mcheck/mce-inject.c b/arch/x86/kernel/cpu/mcheck/mce-inject.c
index 753746f..ddc72f8 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-inject.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-inject.c
@@ -78,6 +78,7 @@ static void raise_exception(struct mce *m, struct pt_regs *pregs)
 }
 
 static cpumask_var_t mce_inject_cpumask;
+static DEFINE_MUTEX(mce_inject_mutex);
 
 static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
 {
@@ -229,7 +230,10 @@ static ssize_t mce_write(struct file *filp, const char __user *ubuf,
 	 * so do it a jiffie or two later everywhere.
 	 */
 	schedule_timeout(2);
+
+	mutex_lock(&mce_inject_mutex);
 	raise_mce(&m);
+	mutex_unlock(&mce_inject_mutex);
 	return usize;
 }
 
-- 
1.7.10.4

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