Re: mixing interupts and threads.

[Matthew Wilcox <matthew@wil.cx>]

On Mon, Jul 07, 2008 at 10:03:26AM +0530, ravikumar wrote:
> 1. Lets suppose i've some critical section and it is synchronized with 
> locks. A thread came and  it's  execution  is in the middle of critical 
> section, at this time an interrupt was occurred which  also executes 
> critical section. As interrupts can't wait on any lock it will get lock 
> and try to execute the critical section and above thread was not yet 
> completed. So inconsistency . How this was handled in Linux.

I recommend you read the excellent
Documentation/DocBook/kernel-locking.tmpl.  If you run 'make pdfdocs',
you can read it as a pdf (other output formats also available).

The short answer to your question is that interrupts should be disabled
while the thread is holding the spinlock.

> 2.Some process is running in kernel mode, at this a kill was sent to 
> this process, does this signal will delivered to the process while it is 
> in kernel mode.

Yes.  If you examine the implementation of, say,
mutex_lock_interruptible(), you'll see how it checks to see whether
signals are pending.  Other functions ending in _interruptible() will
likely do similar checks.

-- 
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