Re: recursive spinlocks. Shoot.

David Woodhouse (dwmw2@infradead.org)
Sun, 18 May 2003 23:34:58 +0100

On Sun, 2003-05-18 at 18:24, Peter T. Breuer wrote:
> The second method is used by programmers who aren't aware that some
> obscure subroutine takes a spinlock, and who recklessly take a lock
> before calling a subroutine (the very thought sends shivers down my
> spine ...). A popular scenario involves not /knowing/ that your routine
> is called by the kernel with some obscure lock already held, and then
> calling a subroutine that calls the same obscure lock. The request
> function is one example, but that's hardly obscure (and in 2.5 the
> situation has eased there!).

To be honest, if any programmer is capable of committing this error and
not finding and fixing it for themselves, then they're also capable, and
arguably _likely_, to introduce subtle lock ordering discrepancies which
will cause deadlock once in a blue moon.

I don't _want_ you to make life easier for this hypothetical programmer.

I want them to either learn to comprehend locking _properly_, or take up
gardening instead.

-- 
dwmw2




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