Messages in this thread | | | Date | Mon, 20 Feb 2017 12:09:41 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v2] x86/mce: Don't participate in rendezvous process once nmi_shootdown_cpus() was made |
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On Mon, Feb 20, 2017 at 02:10:37PM +0800, Xunlei Pang wrote: > @@ -1128,8 +1129,9 @@ void do_machine_check(struct pt_regs *regs, long error_code) > */ > int lmce = 1; > > - /* If this CPU is offline, just bail out. */ > - if (cpu_is_offline(smp_processor_id())) { > + /* If nmi shootdown happened or this CPU is offline, just bail out. */ > + if (cpus_shotdown() ||
I don't like "cpus_shotdown" - it doesn't hint at all that this is special-handling crash/kdump.
And more importantly, I want it to be obvious that we do let the crashing CPU into the MCE handler.
Why?
If we didn't, you will not handle *any* MCE, even a fatal one, during dumping memory so if that dump is corrupted from the MCE, you won't know. And I don't want to be the one staring at the corrupted dump and wondering why I'm seeing what I'm seeing.
IOW, if we get a fatal MCE during dumping then we should go and die. This is much better than silently corrupting the dump and not even saying anything about it.
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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