Re: CVS commit: src/sys/kern

[Michael <macallan%netbsd.org@localhost>]

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Hello,

On May 5, 2009, at 4:26 PM, Manuel Bouyer wrote:

> Module Name:    src
> Committed By:   bouyer
> Date:           Tue May  5 20:26:36 UTC 2009
>
> Modified Files:
>         src/sys/kern: kern_softint.c
>
> Log Message:
> Declare sh_flags volatile.
> Without it, on ports where splhigh() is inline, the compiler will  
> optimise
> the second SOFTINT_PENDING test in softint_schedule(). A dissasembly
> of softint_schedule() with and without the volatile sh_flags confirm  
> this
> on sparc.
> Because of this there is a race that could lead to the softhand_t
> being enqueued twice on si_q, leading to a corrupted queue and
> some handler being SOFTINT_PENDING but never called.
>
> Should fix PR kern/38637

That sounds a lot like a problem I'm trying to track down on macppc  
for a while now ( and yes, spl*() are inlined )

have fun
Michael
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