powerpc/mpic_msgr: add lock for MPIC message global variable
Also fix issue of accessing invalid msgr pointer issue. The local
msgr pointer in fucntion mpic_msgr_get will be accessed before
getting a valid address which will cause kernel crash.
Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/sysdev/mpic_msgr.c b/arch/powerpc/sysdev/mpic_msgr.c
index 6e7fa38..dc1cfe3 100644
--- a/arch/powerpc/sysdev/mpic_msgr.c
+++ b/arch/powerpc/sysdev/mpic_msgr.c
@@ -27,6 +27,7 @@
static struct mpic_msgr **mpic_msgrs;
static unsigned int mpic_msgr_count;
+static DEFINE_RAW_SPINLOCK(msgrs_lock);
static inline void _mpic_msgr_mer_write(struct mpic_msgr *msgr, u32 value)
{
@@ -56,12 +57,11 @@
if (reg_num >= mpic_msgr_count)
return ERR_PTR(-ENODEV);
- raw_spin_lock_irqsave(&msgr->lock, flags);
- if (mpic_msgrs[reg_num]->in_use == MSGR_FREE) {
- msgr = mpic_msgrs[reg_num];
+ raw_spin_lock_irqsave(&msgrs_lock, flags);
+ msgr = mpic_msgrs[reg_num];
+ if (msgr->in_use == MSGR_FREE)
msgr->in_use = MSGR_INUSE;
- }
- raw_spin_unlock_irqrestore(&msgr->lock, flags);
+ raw_spin_unlock_irqrestore(&msgrs_lock, flags);
return msgr;
}