Re: 2.6.15-mm4 failure on power5

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Ingo Molnar <[email protected]> wrote:
>
> 
> * Andrew Morton <[email protected]> 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.]

Small cost, really...
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux