Re: 2.6.15-mm4 failure on power5

From: Ingo Molnar
Date: Wed Jan 18 2006 - 02:02:56 EST



* Andrew Morton <akpm@xxxxxxxx> wrote:

> > [ if this indeed is the case then i'll add irqs_off() checks to
> > DEBUG_MUTEXES=y, to ensure that the mutex APIs are never called with
> > interrupts disabled. ]
>
> Yes, I suppose so. But we're already calling might_sleep(), and
> might_sleep() checks for that. Perhaps the might_sleep() check is
> being defeated by the nasty system_running check.

ah ... indeed.

> There's a sad story behind that system_running check in might_sleep().
> Because the kernel early boot is running in an in_atomic() state, a
> great number of bogus might_sleep() warnings come out because of
> various code doing potentially-sleepy things. I ended up adding the
> system_running test, with the changelog "OK, I give up. Kill all the
> might_sleep warnings from the early boot process." Undoing that and
> fixing up the fallout would be a lot of nasty work.

OTOH, x86 was just fine last i checked, and it has alot more complex
bootup code than any of the other architectures (due to the sheer number
of x86 variants).

Ingo
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