Re: 2.6.15-mm4 failure on power5

Ingo Molnar
2006-01-18T08:08:27Z

* Andrew Morton <akpm@osdl.org> wrote:

> > Yes, which would be why this code never triggered a warning when
> > cpucontrol was a semaphore.
>
> Yup. Perhaps a sane fix which preserves the unpleasant semantics is
> to do irqsave in the mutex debug code.

i'd much rather remove that ugly hack from __might_sleep(). How many
other bugs does it hide? Does it hide bugs that dont normally trigger
during bootups on real hardware, but which could trigger on e.g. UML or
on Xen? I really think such ugly workarounds are not justified, if other
arches can get their act together. Would you make such an exception for
other arches too, like ARM?

an irqsave in the mutex debug code will uglify the kernel/mutex.c code -
i'd have to add extra "unsigned long flags" lines. [It will also slow
down the debug code a bit - an extra PUSHF has to be done.]

Ingo