sgi-xp: nested calls to spin_lock_irqsave()

PATCH In review Dan Carpenter 2 participants 2 messages Dec 15, 2011 – Dec 16, 2011

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Dan Carpenter

author

2011-12-15 06:48 UTC #0 lore raw

PATCH 1/1 sgi-xp: nested calls to spin_lock_irqsave()

The code here has a nested spin_lock_irqsave(). It's not needed since IRQs are already disabled and it causes a problem because it means that IRQs won't be enabled again at the end. The second call to spin_lock_irqsave() will overwrite the value of irq_flags and we can't restore the proper settings.

Signed-off-by Dan Carpenter <[email protected]>

---
This is a static checker fix. It's possible that no one hits this bug in real life if the function is always called with IRQs disabled.

drivers/misc/sgi-xp/xpc_uv.c +2 -2

index 17bbacb..87b251a 100644
@@ -452,9 +452,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
 
 		if (msg->activate_gru_mq_desc_gpa ! 		    part_uv->activate_gru_mq_desc_gpa) {
-			spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
+			spin_lock(&part_uv->flags_lock);
 			part_uv->flags &= ~XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV;
-			spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
+			spin_unlock(&part_uv->flags_lock);
 			part_uv->activate_gru_mq_desc_gpa  			    msg->activate_gru_mq_desc_gpa;
 		}

Robin Holt

Acked-by on v1 1/1

2011-12-16 11:55 UTC #1 lore raw

Quoted 7 lines · Dan Carpenter

The code here has a nested spin_lock_irqsave(). It's not needed since IRQs are already disabled and it causes a problem because it means that IRQs won't be enabled again at the end. The second call to spin_lock_irqsave() will overwrite the value of irq_flags and we can't restore the proper settings.
Signed-off-by Dan Carpenter <[email protected]>

Acked-by Robin Holt <[email protected]>