Why We cant call sleep in linux interrupt handler

In computer systems, an interrupt is a signal that indicates an event that requires the attention of the processor. When an interrupt occurs, the processor stops executing the current task and switches to an interrupt handler routine to process the interrupt. The interrupt handler is a piece of code that runs in a special context, known as an interrupt context. It is important to note that interrupt handling is a time-critical task, and any delay can cause system instability or performance degradation.

One critical issue with interrupt handling is that it is not safe to sleep or block the interrupt handler. Sleeping or blocking the interrupt handler can cause the system to deadlock or become unresponsive, as the interrupt handler is responsible for managing the hardware devices, and any delay can cause the devices to stop functioning correctly. Moreover, sleeping or blocking the interrupt handler can also cause other interrupts to be missed, which can lead to system instability.

When an interrupt handler sleeps, it releases the processor's control, and the system scheduler can schedule other processes to run. However, the interrupt handler needs to finish its execution quickly and return control to the interrupted task to avoid any system instability or performance issues.

To avoid sleeping or blocking the interrupt handler, developers can use techniques such as deferred work or tasklets. Deferred work and tasklets are methods of deferring work that needs to be performed in the interrupt context to a later time when it is safe to do so.

In summary, it is not safe to sleep or block an interrupt handler because it can cause system instability, missed interrupts, and performance degradation. To avoid this issue, developers should use techniques such as deferred work or tasklets to defer work that needs to be performed in the interrupt context to a later time when it is safe to do so.