Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [PATCH] Booting when CPUs fail to come up. | Date | Sun, 22 Feb 2004 12:43:04 +1100 |
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In message <20040221133359.GA339@elf.ucw.cz> you write: > Hi! > > > > > I recently played with setting a bit in cpu_possible_map that wasn't > > > > in cpu_online_map: this can happen without hotplug CPU when a CPU > > > > fails to boot, for example. > > > > > > Is it safe to continue when one cpu is apparently malfunctioning? > > > > Well, patch was overzealous and no longer required. > > > > But we shouldn't crash when this happens just because a CPU didn't > > come up. > > I still do not agree.
You're entitled. However, on x86 we booted before when a secondary CPU didn't come up, and the patch was designed to ensure that we still did so.
> You have a system you tried to kick CPU #13 alive, and something very > wrong happened, CPU #13 did not come up. It is there, has full access > to memory, it is probably running some kind of program....
No, it's possible, but not online. This actually happens on archs where you have hotplug cpus, as well as x86 boot failures.
> I'd not dare mount disks read-write in such situation and I believe > crashing early is actually right thing to do.
Sure, send a patch for x86 to do that, and we can discuss that. I'm not going to break existing behavior by stealth though.
Rusty. -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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