deadlock from spinlock waiting..

[Chan Kim]

Hello,
This is a very basic question and I guess something's wrong in my understanding.
I'm trying to use spinlock but not sure if it's working as I intend to use it for.
The _CORE_spinlock_Wait function seems to be disabling interrupt. the code brief say even task dispatch is disabled.
Then when task A already has the lock, and task B tries to get the lock, how can task A release it if it is not dispatched?
My case right now seems like that. (write task waiting for the lock, but read task has the lock and because interrupt is disabled,  read task cannot process things..)
I'm uinsg version 4.10.99.
Chan