[PATCH 2/5] x86: mce: Serialize mce injection

From: Chen Gong
Date: Thu Jul 19 2012 - 01:59:02 EST

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

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

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

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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.
+ mutex_lock(&mce_inject_mutex);
+ mutex_unlock(&mce_inject_mutex);
return usize;


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