Messages in this thread | | | Date | Wed, 18 Jan 2006 00:24:59 -0800 | From | Andrew Morton <> | Subject | Re: 2.6.15-mm4 failure on power5 |
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Ingo Molnar <mingo@elte.hu> wrote: > > > * 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?
Gee, it was 2.6.0-test9. I don't remember, but I do recall the problems were really really nasty, and what's the point? We're only running one thread on one CPU at that time, so none of these things _will_ sleep.
> 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?
Don't care really, as long as a) the problems don't hit -mm or mainline and b) someone else fixes them. Yes, it'd be nice to fix these things, and we might even find real bugs. Perhaps things are better now, but I suspect it's a can of worms.
> 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.]
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