Hi, I read this article http://www.linuxjournal.com/article/5833 to learn about spinlock. I try this to use it in my kernel driver. Here is what my driver code needs to do: In f1(), it will get the spin lock, and caller can call f2() will wait for the lock since the spin lock is not being unlock. The spin lock will be unlock in my interrupt handler (triggered by the HW). void f1() { spin_lock(&mylock); // write hardware REG_ADDR += FLAG_A; } void f2() { spin_lock(&mylock); //... } The hardware will send the application an interrupt and my interrupt handler will call spin_unlock(&mylock); My question is if I call f1() f2() // i want this to block until the interrupt return saying setting REG_ADDR is done. when I run this, I get an exception in kernel saying a deadlock " INFO: possible recursive locking detected" How can I re-write my code so that kernel does not think I have a deadlock? I want my driver code to wait until HW sends me an interrupt saying setting REG_ADDR is done. Thank you.