Messages in this thread |  | | Date | Sun, 2 Aug 2009 22:41:50 +0200 | From | Ingo Molnar <> | Subject | Re: [tip:core/debug] debug lockups: Improve lockup detection |
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* Andrew Morton <akpm@linux-foundation.org> wrote:
> On Sun, 2 Aug 2009 21:26:57 +0200 Ingo Molnar <mingo@elte.hu> wrote: > > > > I think this just broke all non-x86 non-sparc SMP architectures. > > > > Yeah - it 'broke' them in the sense of them not having a working > > trigger_all_cpu_backtrace() implementation to begin with. > > c'mon. It broke them in the sense that sysrq-l went from "works" > to "doesn't work".
You are right (i broke it with my patch) but the thing is, sysrq-l almost useless currently: it uses schedule_work() which assumes a mostly working system with full irqs and scheduling working fine. Now, i dont need sysrq-l on mostly working systems.
So the 'breakage' is of something that was largely useless: and now you put the onus of implementing it for _all_ architectures (which i dont use) on me?
If that's the requirement then i'll have to keep this as a local debug hack and not do an upstream solution - i dont have the resources to do it for all ~10 SMP architectures.
sysrq-l has been messed up really and now that messup limits the adoption of the much more useful solution? I didnt make this thing up, i tried to use it on a locked up system and wondered why it emits nothing and why it uses a separate facility instead of an existing trigger-backtraces facility (which the spinlock-debug code uses).
> It would take months for the relevant arch maintainers to even > find out about this, after which they're left with dud kernels out > in the field. > > It's better to break the build or to emit warnings than to > silently and secretly break their stuff.
But that warning will bounce the ball back to me, wont it? My patch will be blamed for 'breaking' those architectures, right?
Ingo
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