linux-next: PowerPC WARN_ON_ONCE() after merge of the final tree (tip related)
Ingo Molnar
mingo at elte.hu
Thu Apr 15 17:32:56 EST 2010
* David Miller <davem at davemloft.net> wrote:
> From: Ingo Molnar <mingo at elte.hu>
> Date: Thu, 15 Apr 2010 08:49:40 +0200
>
> > Btw., WARN_ON trapping on PowerPC is clearly a PowerPC bug - there's a good
> > reason we have WARN_ON versus BUG_ON - it should be fixed.
>
> I disagree, an implementation should be allowed to use the most
> efficient implementation possible for both interfaces.
It trades robustness for slightly better space/code efficiency.
Such a trap based mechanism exists on x86 as well and we use it for BUG_ON().
We intentionally dont use it to generate warnings and dont override __WARN(),
because it would blow up way too often when a warning triggers in some
sensitive codepath that cannot take a trap.
Anyway, the warning obviously has to be fixed - but the boot crash itself is
PowerPC's own doing.
Ingo
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